Electromagnetic wave detector and array of electromagnetic wave detectors

Abstract

An electromagnetic wave detection device includes at least one photoelectric conversion element and a plasmonic filter (3) disposed in opposition to the at least one photoelectric conversion element. A plurality of through holes (30) are periodically formed in the plasmonic filter (3). The at least one photoelectric conversion element includes a semiconductor layer (2) having a region (20) overlapping at least one of the plurality of through holes in plan view, an insulating layer (4) formed so as to cover a portion of the region (20), a two-dimensional material layer (1) disposed on the other portion of the region (20) and the insulating layer (4) and electrically connected to the other portion of the region (20), a first electrode portion (5) electrically connected to the two-dimensional material layer (1), and a second electrode portion (6) electrically connected to the semiconductor layer (2).

Description

Technical Field

[0001] This disclosure relates to electromagnetic wave detectors and electromagnetic wave detector arrays. Background Technology

[0002] Previously, graphene, a two-dimensional material layer known for its extremely high mobility, has been used as a material for electromagnetic wave detection layers in next-generation electromagnetic wave detectors. Graphene's absorption rate is as low as 2.3%. Therefore, methods for increasing sensitivity in electromagnetic wave detectors using graphene have been proposed. For example, in U.S. Patent Application Publication No. 2015 / 0243826 (Patent Document 1), a detector with the following structure is proposed. In the detector of Patent Document 1, two or more dielectric layers are provided on an n-type semiconductor layer. A graphene layer is formed on the two dielectric layers and on the surface portion of the n-type semiconductor layer located between the two dielectric layers. The graphene layer and the n-type semiconductor layer are Schottky-junctioned. Source / drain electrodes connected to both ends of the graphene layer are disposed on the dielectric layer. A gate electrode is connected to the n-type semiconductor layer. When a voltage is applied between the gate electrode and the source or drain electrode, a turn-off operation can be performed through the aforementioned Schottky junction.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: U.S. Patent Application Publication No. 2015 / 0243826 Summary of the Invention

[0006] The aforementioned conventional detectors are sensitive to electromagnetic waves with energies above the band gap of the semiconductor layer in contact with the graphene layer. In other words, the detection wavelength of these detectors is below the wavelength corresponding to the band gap of the semiconductor layer. Therefore, in these detectors, it is difficult to selectively detect electromagnetic waves of only a specific wavelength band.

[0007] Furthermore, in the detectors described above, the sensitivity of the detector during Schottky operation, where voltage is applied to the gate electrode and the source electrode or drain electrode, depends on the quantum efficiency of the semiconductor layer, making it difficult to achieve high sensitivity in the detector.

[0008] The main objective of this disclosure is to provide an electromagnetic wave detector and an electromagnetic wave detector array that, compared to the conventional detectors described above, can selectively detect only electromagnetic waves in a specific wavelength band and has high detection sensitivity.

[0009] The electromagnetic wave detector disclosed herein includes at least one photoelectric conversion element and a plasma filter arranged opposite to the at least one photoelectric conversion element. A plurality of through-holes are periodically formed in the plasma filter. The at least one photoelectric conversion element includes: a semiconductor layer having a region that overlaps with at least one of the plurality of through-holes when viewed from above; an insulating layer formed to cover a portion of the region; a two-dimensional material layer disposed on and electrically connected to the other portion of the region and the insulating layer; a first electrode portion electrically connected to the two-dimensional material layer; and a second electrode portion electrically connected to the semiconductor layer.

[0010] According to this disclosure, an electromagnetic wave detector and an electromagnetic wave detector array can be provided that, compared to the conventional detectors described above, can selectively detect only electromagnetic waves in specific wavelength bands and have high detection sensitivity. Attached Figure Description

[0011] Figure 1 This is a cross-sectional view showing the electromagnetic wave detector according to Embodiment 1.

[0012] Figure 2 yes Figure 1 The image shows a top view of the electromagnetic wave detector.

[0013] Figure 3 yes Figure 1 The top view of the plasma filter of the electromagnetic wave detector shown.

[0014] Figure 4 This is a cross-sectional view showing the electromagnetic wave detector according to Embodiment 2.

[0015] Figure 5 This is a cross-sectional view showing a modified example of the electromagnetic wave detector according to Embodiment 2.

[0016] Figure 6 This is a cross-sectional view showing the electromagnetic wave detector according to Embodiment 3.

[0017] Figure 7 This is a cross-sectional view showing the electromagnetic wave detector according to Embodiment 4.

[0018] Figure 8 This is a top view showing the plasma filter of the electromagnetic wave detector according to Embodiment 5.

[0019] Figure 9 This is a top view showing the plasma filter of the electromagnetic wave detector according to Embodiment 6.

[0020] Figure 10 This is a top view showing a further variation of the plasma filter of the electromagnetic wave detector according to Embodiment 6.

[0021] Figure 11 This is a cross-sectional view showing the electromagnetic wave detector according to Embodiment 7.

[0022] Figure 12 This is a cross-sectional view showing the electromagnetic wave detector according to Embodiment 8.

[0023] Figure 13 yes Figure 12 The image shows a top view of the electromagnetic wave detector.

[0024] Figure 14 This is a cross-sectional view showing the electromagnetic wave detector according to Embodiment 9.

[0025] Figure 15 This is a cross-sectional view showing the electromagnetic wave detector according to Embodiment 10.

[0026] Figure 16 This is a cross-sectional view showing the electromagnetic wave detector according to Embodiment 11.

[0027] Figure 17 This is a top view showing the electromagnetic wave detector according to Embodiment 12.

[0028] Figure 18 It is along Figure 17 A cross-sectional view of line segment XVIII-XVIII in the diagram.

[0029] Figure 19 This is a top view showing the electromagnetic wave detector according to embodiment 13.

[0030] Figure 20 It is along Figure 19 A cross-sectional view of line segment XX-XX in the diagram.

[0031] Figure 21 This is a cross-sectional view showing a modified example of the electromagnetic wave detector according to Embodiment 13.

[0032] Figure 22 This is a cross-sectional view showing the electromagnetic wave detector according to Embodiment 14.

[0033] Figure 23 This is a cross-sectional view showing the electromagnetic wave detector according to Embodiment 15.

[0034] Figure 24 This is a cross-sectional view showing a modified example of the electromagnetic wave detector according to Embodiment 15.

[0035] Figure 25 This is a cross-sectional view showing the electromagnetic wave detector according to Embodiment 16.

[0036] Figure 26 This is a partial cross-sectional view of the plasma filter of the electromagnetic wave detector according to Embodiment 19.

[0037] Figure 27 This is a partial top view of the plasma filter of the electromagnetic wave detector according to Embodiment 20.

[0038] Figure 28 From Figure 27 The arrows XXVIII-XXVIII in the image show a partial cross-sectional view of the plasma filter.

[0039] Figure 29 This is a top view showing the electromagnetic wave detector array according to embodiment 21.

[0040] Figure 30 This is a top view showing a modified example of the electromagnetic wave detector array according to Embodiment 21.

[0041] (Symbol Explanation)

[0042] 1: Two-dimensional material layer; 1a: Part 1; 1b: Part 2; 1c: Part 3; 2: Semiconductor layer; 2A: Surface 1; 2B: Surface 2; 3: Plasma filter; 3A: Surface 3; 3B: Surface 4; 3C: Inner peripheral surface; 4: Insulating layer; 4C: Inclined surface; 4a, 4b: Parts; 5: First electrode portion; 6: Second electrode portion; 7: Buffer layer; 8: Connecting conductor; 9: Contact layer; 10: First component; 11: Second component ; 20: Region; 21: First semiconductor portion; 22: Second semiconductor portion; 23: Bonding interface; 24: Protrusion; 30: Through hole; 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 200, 201, 202, 203: Electromagnetic wave detectors; 300, 301: Electromagnetic wave detector array. Detailed Implementation

[0043] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. The drawings are schematic diagrams, conceptually illustrating functions or structures. Furthermore, the present disclosure is not limited to the embodiments described below. Except as specifically described, the basic structure of the electromagnetic wave detector is common in all embodiments. Additionally, portions marked with the same reference numerals are the same as or equivalent to those described above. This is consistent throughout the specification.

[0044] The wavelength band of the electromagnetic wave detector involved in this embodiment is not particularly limited. The electromagnetic wave detector involved in this embodiment is, for example, a detector that detects electromagnetic waves such as visible light, infrared light, near-infrared light, ultraviolet light, X-rays, terahertz (THz) waves, or microwaves. Furthermore, in this embodiment of the invention, these lights and radio waves are collectively referred to as electromagnetic waves. Additionally, any wavelength within the wavelength band of the electromagnetic wave detector involved in this embodiment is referred to as the detection wavelength.

[0045] Furthermore, the electromagnetic wave detector involved in this embodiment can be configured to detect electromagnetic waves of only one wavelength band, or it can be configured to detect electromagnetic waves of multiple different wavelength bands. In other words, the detection wavelength of the electromagnetic wave detector involved in this embodiment can be either only one or multiple.

[0046] In addition, in this embodiment, the term p-type graphene or n-type graphene is used as an example of a two-dimensional material layer, but graphene with more holes than intrinsic graphene is called p-type, and graphene with more electrons is called n-type.

[0047] Furthermore, in this embodiment, the terms n-type or p-type are used to describe the material of the contact layer disposed on graphene, which is an example of a two-dimensional material layer. For example, n-type indicates an electron-donating material, and p-type indicates an electron-withdrawing material. Additionally, in the molecular whole, a state where electrons dominate is called n-type, and a state where holes dominate is called p-type, based on the visible shift in charge within the molecule. The materials for these contact layers can be either organic or inorganic, or mixtures thereof.

[0048] Furthermore, phenomena referred to as plasmon resonance, such as surface plasmon resonance as an interaction between a metal surface and light; phenomena applied to a metal surface outside the visible / near-infrared light domain, which are called suspected surface plasmon resonances; and phenomena referred to as metamaterials or plasmon metamaterials, which are constructed to manipulate specific wavelengths through sub-wavelength structures, are not specifically distinguished by their names and are treated equally in terms of the effects they produce. Here, these resonances will be referred to as surface plasmon resonances, plasmon resonances, or simply resonances.

[0049] Furthermore, surface plasmon resonance is generally characterized by the propagation or confinement of electromagnetic waves at the interface between a metal and a dielectric. However, in recent years, surface plasmon resonance has also been found in materials other than metals, such as titanium oxide and graphene. In this embodiment, without distinguishing between such materials, a material that generates surface plasmon resonance (surface plasmons are resonantly excited) when an electromagnetic wave of the detection wavelength is incident is referred to as a plasmon resonance material. In this embodiment, at least a portion of the material constituting the surface of the plasmon filter includes a plasmon resonance material.

[0050] Furthermore, when the electromagnetic wave detector involved in this embodiment is in operation, the layer that does not generate tunneling current is called an insulating layer, and the layer that can generate tunneling current is called a buffer layer.

[0051] Furthermore, in this embodiment, the material constituting the two-dimensional material layer can be any material capable of arranging atoms in a single layer within a two-dimensional plane. For example, it can include at least one material selected from the group consisting of graphene, transition metal dichalcogenides (TMD), black phosphorus, silicene (a two-dimensional honeycomb structure composed of silicon atoms), and germanene (a two-dimensional honeycomb structure composed of germanium atoms). Examples of transition metal dichalcogenides include molybdenum disulfide (MoS2), tungsten disulfide (WS2), and tungsten diselenide (WSe2). The two-dimensional material layer composed of at least any of the above materials achieves substantially the same effect as the two-dimensional material layer composed of graphene described later.

[0052] Implementation method 1.

[0053] like Figure 1 as well as Figure 2 As shown, the electromagnetic wave detector 100 according to Embodiment 1 includes multiple photoelectric conversion elements and a plasma filter 3. Each photoelectric conversion element mainly includes a two-dimensional material layer 1, a semiconductor layer 2, an insulating layer 4, a first electrode portion 5, and a second electrode portion 6. Each photoelectric conversion element can constitute one pixel. The two-dimensional material layer 1 and the first electrode portion 5 of each photoelectric conversion element are independently provided with corresponding portions of other photoelectric conversion elements. The semiconductor layer 2 and the second electrode portion 6 of each photoelectric conversion element are integrally provided with corresponding portions of other photoelectric conversion elements. The insulating layer 4 of each photoelectric conversion element is, for example, independently provided with the insulating layer 4 of other photoelectric conversion elements. Alternatively, the insulating layer 4 of each photoelectric conversion element may be integrally provided with the insulating layer 4 of other photoelectric conversion elements.

[0054] The plasma filter 3 is arranged to face each of the plurality of photoelectric conversion elements. The plasma filter 3 has a third surface 3A facing the first surface 2A of the semiconductor layer 2 (described later) and a fourth surface 3B located on the opposite side of the third surface 3A. The third surface 3A is in contact with the first surface 2A of the semiconductor layer 2, for example. The fourth surface 3B is in contact with the insulating layer 4.

[0055] The plasma filter 3 is configured to allow electromagnetic waves within the wavelength band detected by the electromagnetic wave detector 100 to transmit only from the fourth surface 3B side to the third surface 3A side (semiconductor layer 2 side). In other words, the plasma filter 3 is configured to generate surface plasmon resonance when an incident electromagnetic wave of the detection wavelength is received. The wavelength band that excites the surface plasmon and the wavelength band in which the semiconductor layer 2 has sensitivity share a common wavelength domain in the plasma filter 3. Generally, it is assumed that the wavelength band that excites the surface plasmon is narrower than the wavelength band in which the semiconductor layer 2 has sensitivity. However, there are other possibilities, not limited to this, where the wavelength band that excites the surface plasmon is widened as described later.

[0056] like Figures 1-3 As shown, the plasma filter 3 has a plurality of through holes 30 extending from the third surface 3A to the fourth surface 3B. The number of through holes 30 is, for example, three or more. The plurality of through holes 30 are arranged periodically, for example, along the third surface 3A in two intersecting directions. Periodic arrangement means a unit periodic arrangement consisting of two or more through holes 30. The plurality of through holes 30 are arranged, for example, at equal intervals. Alternatively, they may be arranged in a unit periodic arrangement consisting of three or more through holes 30. Furthermore, the plurality of through holes 30 may also be arranged periodically with intervals between them in at least one direction along the third surface 3A.

[0057] The material constituting all surfaces of the plasma filter 3 may include, for example, the aforementioned plasma resonant material. Alternatively, the material constituting at least a portion of the surfaces of the plasma filter 3 may contain the plasma resonant material. For example, the material constituting at least the fourth surface 3B of the plasma filter 3 and the inner peripheral surfaces of each of the plurality of through holes 30 may contain the plasma resonant material.

[0058] The plasma filter 3 can generate surface plasmon resonance when electromagnetic waves of the detection wavelength are incident, and the opening width, depth (thickness of the plasma filter 3), and spacing P (period, reference) between the central axes C of two adjacent through holes 30 can be arbitrarily selected according to the detection wavelength. Figure 3 And the aforementioned plasma resonance material. The opening width of each through-hole 30 is, for example, shorter than the detection wavelength.

[0059] Regarding the planar shape of the multiple through holes 30, it can be any shape as long as surface plasmon resonance is generated in the plasma filter 3 when an electromagnetic wave of the detection wavelength is incident, for example, Figure 3 The diagram shows a circle. Furthermore, the planar shape of the plurality of through-holes 30 can also be, for example, a square, rectangle, ellipse, triangle, bullseye shape (a shape consisting of a circle or ring and concentric rings arranged around it), fractal shape, or cross shape. When the planar shape of the plurality of through-holes 30 is cross-shaped, surface plasmon resonance occurs when the plasma filter 3 is irradiated with two or more electromagnetic waves of different detection wavelengths. Additionally, the planar shapes of the plurality of through-holes 30 can also be different from each other. The plurality of through-holes 30 can also have a first through-hole and a second through-hole with the same planar shape as the first through-hole but a different size.

[0060] Semiconductor layer 2 has a first surface 2A and a second surface 2B located on the side opposite to the first surface 2A. For example... Figure 1 as well as Figure 2 As shown, a two-dimensional material layer 1, a plasma filter 3, an insulating layer 4, and a first electrode portion 5 are disposed on the first surface 2A of the semiconductor layer 2. A second electrode portion 6 is disposed on the second surface 2B of the semiconductor layer 2. An electromagnetic wave detector 100 detects electromagnetic waves incident on the semiconductor layer 2 from the side where the plasma filter 3 is disposed.

[0061] The semiconductor layer 2 has multiple regions 20 that overlap with multiple through-holes 30 when viewed from above. Each region 20 is a columnar region having a first surface 2A and a second surface 2B. The first surface 2A of the regions other than the multiple regions 20 is in contact with the third surface 3A of the plasma filter 3. The first surface 2A of each region 20 has a first contact region that contacts a first portion of the two-dimensional material layer 1 (described later), a second contact region that contacts a portion of the insulating layer 4, and a region exposed from the two-dimensional material layer 1, the plasma filter 3, and the insulating layer 4 when viewed from above. The entire second surface 2B is in contact with the second electrode portion 6.

[0062] Semiconductor layer 2 is sensitive to the detection wavelength. That is, semiconductor layer 2 is configured to generate photocarriers within semiconductor layer 2 when an electromagnetic wave of the detection wavelength is incident on semiconductor layer 2. As described above, there is a common wavelength domain in the wavelength band where semiconductor layer 2 is sensitive and in the wavelength band where surface plasma is excited in plasma filter 3.

[0063] The semiconductor material constituting semiconductor layer 2 can be arbitrarily selected based on the detection wavelength. The material constituting semiconductor layer 2 can be any semiconductor material, for example, any semiconductor material belonging to group IV, any compound semiconductor material belonging to groups III-V, or any compound semiconductor material belonging to groups II-VI. The material constituting semiconductor layer 2 may also include at least one material selected from the group consisting of silicon (Si), germanium (Ge), cadmium mercury telluride (HgCdTe), indium antimonide (InSb), lead selenide (PbSe), lead sulfide (PbS), cadmium sulfide (CdS), gallium nitride (GaN), silicon carbide (SiC), gallium phosphide (GaP), indium gallium arsenide (InGaAs), gallium arsenide (GaAs), and indium arsenide (InAs). Semiconductor layer 2 may have at least one of a quantum well and a quantum dot, or it may have a superlattice (e.g., a Type II superlattice) with such a quantum structure periodically arranged. Semiconductor layer 2 may also have a pn junction.

[0064] Furthermore, when the electromagnetic wave detector 100 has multiple detection wavelengths, the semiconductor layer 2 is configured as an assembly of multiple semiconductor layers that are sensitive to different detection wavelengths.

[0065] Preferably, the semiconductor layer 2 is doped with impurities to make its resistivity below 100 Ω·cm. By doping the semiconductor layer 2 with a high concentration, the movement speed of charge carriers in the semiconductor layer 2 (readout speed) increases. As a result, the response speed of the electromagnetic wave detector is improved.

[0066] The insulating layer 4 is formed to cover a portion of the first surface 2A (the second contact area) of the aforementioned region 20. The insulating layer 4 extends from the second contact area to a portion of the fourth surface 3B of the plasma filter 3. In other words, the insulating layer 4 has a portion 4a disposed on the second contact area and a portion 4b disposed on the plasma filter 3. The portion 4a of the insulating layer 4 contacts the second contact area, a portion of the inner peripheral surface of the through-hole 30 of the plasma filter 3, and the second portion 1b of the two-dimensional material layer 1 described later. The portion 4b of the insulating layer 4 contacts the third portion 1c of the two-dimensional material layer 1 described later and a portion of the fourth surface 3B of the plasma filter 3. The portion 4b is connected to the upper end of the portion 4a. Figure 1 As shown, the insulating layer 4 is formed in a stepped manner.

[0067] The insulating layer 4 electrically insulates the semiconductor layer 2, the second portion of the two-dimensional material layer 1 (described later), and the first electrode portion 5. Regarding the thickness of the insulating layer 4, there are no particular limitations as long as no tunneling current is generated between the second portion of the two-dimensional material layer 1 and the first electrode portion 5 and the semiconductor layer 2 when the electromagnetic wave detector 100 is activated. Preferably, from the viewpoint of improving the light-blocking effect (described later), the thickness of the insulating layer 4 is as thin as possible.

[0068] As the insulating layer 4, an insulating film made of silicon oxide can be used, for example. Furthermore, the material constituting the insulating layer 4 can be any insulating material with electrical insulating properties, and is not limited to silicon oxide. For example, the material constituting the insulating layer 4 may also include at least one material selected from the group consisting of silicon oxide, tetraethyl orthosilicate, silicon nitride, hafnium oxide, aluminum oxide, nickel oxide, boron nitride, and siloxane-based polymer materials. For example, since boron nitride has an atomic arrangement similar to graphene, it will not adversely affect charge mobility even when in contact with the two-dimensional material layer 1 made of graphene. Therefore, from the viewpoint of suppressing the properties of the two-dimensional material layer 1, such as the resistance of the insulating layer 4 to electron mobility, boron nitride is suitable as a material constituting the insulating layer 4.

[0069] Two-dimensional material layer 1 extends from the first contact region of region 20 to the insulating layer 4 disposed on the plasma filter 3. Two-dimensional material layer 1 has a first portion 1a disposed on another part of the first surface 2A of region 20 (the first contact region), a second portion 1b disposed on the aforementioned portion 4a of the insulating layer 4, and a third portion 1c disposed on the plasma filter 3 and the aforementioned portion 4b of the insulating layer 4. The first portion 1a of two-dimensional material layer 1 is disposed on region 20 without being separated from the insulating layer 4. The first portion 1a is electrically connected, for example, to the aforementioned first contact region of semiconductor layer 2. Preferably, the first portion 1a is Schottky-bonded to semiconductor layer 2. The second portion 1b is configured to provide an electric field effect through photocarriers generated in semiconductor layer 2. The first portion 1a and the third portion 1c function as source / drain regions in the opto-blocking effect described later. The second portion 1b functions as a channel region in the opto-blocking effect described later.

[0070] like Figure 1 As shown, the two-dimensional material layer 1 is formed in a stepped manner. The number of steps in the two-dimensional material layer 1 is, for example, one more than the number of steps in the insulating layer 4, and is two. The first part 1a of the two-dimensional material layer 1 has one end in the length direction of the two-dimensional material layer 1. The third part 1c of the two-dimensional material layer 1 has the other end in the length direction of the two-dimensional material layer 1.

[0071] Two-dimensional material layer 1 can be, for example, a single layer of graphene. A single layer of graphene is a single-atom layer of two-dimensional carbon crystals. Furthermore, each chain in the single-layer graphene is arranged in a hexagonal shape and contains carbon atoms. Alternatively, two-dimensional material layer 1 can also be configured as multilayer graphene, consisting of two or more layers of single-layer graphene. Additionally, undoped graphene or graphene doped with p-type or n-type impurities can be used as two-dimensional material layer 1.

[0072] When multilayer graphene is used in the two-dimensional material layer 1, the photoelectric conversion efficiency of the two-dimensional material layer 1 increases, and the sensitivity of the electromagnetic wave detector becomes higher. The multilayer graphene used as the two-dimensional material layer 1 can have either inconsistent or consistent orientations of the lattice vectors of the hexagonal lattice in any two layers of graphene. For example, by stacking two or more layers of graphene, a band gap is formed in the two-dimensional material layer 1. As a result, a wavelength selectivity effect for the electromagnetic waves in photoelectric conversion can be added. Furthermore, as the number of layers in the multilayer graphene constituting the two-dimensional material layer 1 increases, the carrier mobility in the channel region decreases. On the other hand, in this case, the two-dimensional material layer 1 is less susceptible to carrier scattering from substrate structures such as substrates, resulting in a lower noise level. Therefore, regarding electromagnetic wave detectors using multilayer graphene as the two-dimensional material layer 1, increased light absorption improves the detection sensitivity of electromagnetic waves.

[0073] Furthermore, when the two-dimensional material layer 1 is in contact with the first electrode portion 5, charge carriers are doped from the first electrode portion 5 into the two-dimensional material layer 1. For example, when gold (Au) is used as the material of the first electrode portion 5, holes are doped into the two-dimensional material layer 1 near the first electrode portion 5 based on the difference in work function between the two-dimensional material layer 1 and Au. When the electromagnetic wave detector is driven in an electron conduction state in this state, the mobility of electrons flowing through the channel region of the two-dimensional material layer 1 decreases due to the influence of holes doped from the first electrode portion 5 into the two-dimensional material layer 1, and the contact resistance between the two-dimensional material layer 1 and the first electrode portion 5 increases. Due to this increase in contact resistance, the mobility of electrons (charge carriers) in the electromagnetic wave detector based on the electric field effect decreases, and the performance of the electromagnetic wave detector may be degraded. In particular, when monolayer graphene is used as the two-dimensional material layer 1, the doping amount of charge carriers injected from the first electrode portion 5 is large. Therefore, the aforementioned decrease in the mobility of electrons in the electromagnetic wave detector is particularly significant when monolayer graphene is used as the two-dimensional material layer 1. Therefore, when all two-dimensional material layers 1 are formed by a single layer of graphene, there is a possibility that the performance of the electromagnetic wave detector will be reduced.

[0074] Therefore, the first portion 1a of the two-dimensional material layer 1, where carriers from the first electrode portion 5 are easily doped, can also be composed of multilayer graphene. Multilayer graphene results in less carrier doping from the first electrode portion 5 compared to single-layer graphene. Therefore, the increase in contact resistance between the two-dimensional material layer 1 and the first electrode portion 5 can be suppressed. As a result, the decrease in electron mobility in the electromagnetic wave detector can be suppressed, and the performance of the electromagnetic wave detector can be improved. In this case, the second portion 1b of the two-dimensional material layer 1 can also be composed of single-layer graphene. That is, the first portion 1a and the third portion 1c, which function as source / drain regions in the two-dimensional material layer 1, can be composed of multilayer graphene, and the second portion 1b, which functions as a channel region, can be composed of single-layer graphene. Thus, compared to the case where the entire two-dimensional material layer 1 is composed of single-layer graphene, the mobility is higher; compared to the case where the entire two-dimensional material layer 1 is composed of multilayer graphene, the mobility of the channel region is improved, thereby improving the performance of the electromagnetic wave detector 100.

[0075] Furthermore, graphene nanoribbons (hereinafter also referred to as graphene nanoribbons) can also be used as the two-dimensional material layer 1. In this case, the two-dimensional material layer 1 can be any structure, such as a graphene nanoribbon monomer, a composite of multiple stacked graphene nanoribbons, or a structure in which graphene nanoribbons are periodically arranged on a plane. For example, when a structure in which graphene nanoribbons are periodically arranged is used as the two-dimensional material layer 1, plasmon resonance can occur in the graphene nanoribbons. As a result, the sensitivity of the electromagnetic wave detector can be improved. Here, the structure in which graphene nanoribbons are periodically arranged is sometimes also referred to as a graphene metamaterial. Therefore, even in an electromagnetic wave detector in which a graphene metamaterial is used as the two-dimensional material layer 1, the above-mentioned effect can be obtained.

[0076] The first electrode portion 5 is disposed on the aforementioned portion 4b of the insulating layer 4 and is electrically connected to the third portion 1c of the two-dimensional material layer 1. The first electrode portion 5 is disposed, for example, on the third portion 1c of the two-dimensional material layer 1. In a top view, the first electrode portion 5 is disposed in a manner that overlaps with the plasma filter 3, the portion 4b of the insulating layer 4, and the third portion 1c of the two-dimensional material layer 1. In a top view, the first electrode portion 5 is disposed, for example, not overlapping with region 20. The second electrode portion 6 is disposed on the second surface 2B of the semiconductor layer 2.

[0077] As for the materials constituting the first electrode portion 5 and the second electrode portion 6, any material can be used as long as it is a conductor. The materials constituting the first electrode portion 5 and the second electrode portion 6 include, for example, at least one selected from the group consisting of gold (Au), silver (Ag), copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr), and palladium (Pd).

[0078] Alternatively, a close-bonding layer (not shown) may be formed between the second electrode portion 6 and the semiconductor layer 2. The close-bonding layer improves the adhesion between the second electrode portion 6 and the semiconductor layer 2. The material constituting the close-bonding layer may include, for example, at least one of chromium (Cr) and titanium (Ti).

[0079] Furthermore, there are no particular restrictions regarding the relative positional relationship between the third portion 1c of the two-dimensional material layer 1 and the first electrode portion 5, as long as they are electrically connected to each other on the aforementioned portion 4b of the insulating layer 4. For example, the first electrode portion 5 may be disposed on the insulating layer 4 and positioned lower than the third portion 1c of the two-dimensional material layer 1. In this case, a close-fitting layer may be formed between the first electrode portion 5 and the insulating layer 4. The close-fitting layer improves the adhesion between the first electrode portion 5 and the insulating layer 4. The material constituting the close-fitting layer may include, for example, at least one of Cr and Ti.

[0080] Alternatively, a protective film (not shown) can be formed on the two-dimensional material layer 1. The protective film can also be provided to cover the two-dimensional material layer 1, the semiconductor layer 2, and the area surrounding the first electrode portion 5. Any material can be used as the material constituting the protective film, but for example, an insulating film made of silicon oxide can be used. Insulators such as oxides or nitrides, such as silicon oxide, silicon nitride, hafnium oxide, aluminum oxide, and boron nitride, can also be used as the material constituting the protective film. The protective film can also be formed by embedding through-holes 30. In this case, the plasma resonance wavelength changes due to the effect of the refractive index of the protective film, but the wavelength selectivity remains unchanged.

[0081] In the electromagnetic wave detector 100, each through-hole 30 can be captured as a detection unit, in which case the number of photoelectric conversion elements is equal to the number of through-holes 30. Therefore, by appropriately reading out signals from each photoelectric conversion element, the electromagnetic wave detector 100 can constitute an image sensor. The signal readout method can, for example, be a method generally used in conventional image sensors.

[0082] The spacing between the centers of two adjacent through holes 30 may not be constant. In this case, the wavelength (resonance wavelength) of the electromagnetic waves that the plasma filter 3 can transmit may be multiple or broadband. In addition, the multiple through holes 30 may also have a first group of through holes that are adjacent to each other separated by a first spacing and a second group of through holes that are adjacent to each other separated by a second spacing different from the first spacing.

[0083] <Manufacturing Method of Electromagnetic Wave Detector>

[0084] First, prepare semiconductor layer 2. For example, prepare semiconductor layer 2 as a flat substrate made of silicon or the like.

[0085] Next, a second electrode portion 6 is formed on the second surface 2B of the semiconductor layer 2. Specifically, a protective film is first formed on the first surface 2A of the semiconductor layer 2. For example, a photoresist is used as the protective film. In this state, the second electrode portion 6 is formed on the second surface 2B of the semiconductor layer 2. Alternatively, to improve the adhesion between the semiconductor layer 2 and the second electrode portion 6, a bonding layer may be formed on the back side of the semiconductor layer 2 before the second electrode portion 6, as described above. Furthermore, this process can be performed after the subsequent processes, as long as it protects the structure on the first surface 2A of the semiconductor layer 2. After this process, the protective film formed on the first surface 2A is removed.

[0086] Next, a plasma filter 3 is formed on the first surface 2A of the semiconductor layer 2. In one example of this process, firstly, a film of the aforementioned plasma resonance material is deposited on the first surface 2A. The film deposition method is not particularly limited; for example, sputtering or vapor deposition can be used. Next, a photoresist mask is formed on the film composed of the plasma resonance material using photolithography or EB painting. The photoresist mask is formed such that only the area where the plurality of through-holes 30 should be formed is exposed in the film, while the area outside is covered. Then, the film is partially removed as a mask by wet etching and dry etching. As a result, a portion of the film remains under the photoresist mask. This portion of the film becomes the plasma filter 3. Then, the photoresist mask is removed. Thus, the plasma filter 3 is formed. Simultaneously, a plurality of regions 20 are formed on the semiconductor layer 2 that overlap with the plurality of through-holes 30 when viewed from above.

[0087] In other examples of this process, firstly, a photoresist mask is formed on the first surface 2A of the semiconductor layer 2 using photolithography or EB drawing. This photoresist mask is formed such that only areas outside the multiple regions 20 (in other words, areas where the plasma filter 3 should be formed) are exposed in the semiconductor layer 2, while covering the multiple regions 20 (in other words, areas where the multiple through-holes 30 should be formed). Then, the aforementioned plasma resonance material is deposited on the photoresist mask. The film formation method is not particularly limited; for example, sputtering or vapor deposition can be used. At this time, the film is formed such that it extends from the interior of the opening of the photoresist mask to the upper surface of the photoresist mask. Then, by removing the photoresist mask along with a portion of the film, the remaining portion of the film disposed at the opening of the photoresist mask remains on the multiple regions 20 of the semiconductor layer 2, becoming the plasma filter 3. This method is generally referred to as a stripping method.

[0088] Next, an insulating layer 4 is formed on the first surface 2A of the semiconductor layer 2 and the fourth surface 3B of the plasma filter 3. Specifically, firstly, an insulating film corresponding to the insulating layer 4 is formed on the first surface 2A of the semiconductor layer 2 and the fourth surface 3B of the plasma filter 3. The film formation method is not particularly limited. For example, if the material constituting the semiconductor layer 2 is silicon and the material constituting the insulating layer 4 is silicon oxide (SiO2), a portion of the aforementioned region 20 of the semiconductor layer 2 can be partially thermally oxidized. Alternatively, the film formation method can be CVD (Chemical Vapor Deposition) or sputtering. Next, a photoresist mask is formed on the insulating film that is to be the insulating layer 4 using photolithography or EB drawing. The photoresist mask is formed such that it covers only the area where the insulating layer 4 is to be formed in the insulating film, leaving the remaining areas exposed. Then, the insulating film is partially removed by wet etching and dry etching, using the photoresist mask as a mask. As a result, a portion of the insulating film remains under the photoresist mask. A portion of the insulating film becomes insulating layer 4. The resist mask is then removed. Thus, insulating layer 4 is formed. Insulating layer 4 has a portion 4a disposed on the second contact region of region 20 and a portion 4b disposed on the fourth surface 3B of the plasma filter 3.

[0089] Next, a two-dimensional material layer 1 is formed on the first contact area of ​​each region 20 and on the insulating layer 4. Specifically, firstly, a two-dimensional material film corresponding to the two-dimensional material layer 1 is formed on the first surface 2A. The film formation method is not particularly limited; for example, epitaxial growth can be used. Alternatively, a two-dimensional material film pre-formed by CVD or the like can be transferred onto the first surface 2A and adhered. Furthermore, if the material constituting the two-dimensional material layer 1 includes graphene, graphene peeled from highly oriented thermally decomposed graphite (HOPG) by mechanical exfoliation can be transferred onto the first surface 2A and adhered. Next, a photoresist mask is formed on the two-dimensional material film using photolithography or EB drawing. The photoresist mask is formed such that it only covers the area in the two-dimensional material film where the two-dimensional material layer 1 should be formed. Then, for example, the two-dimensional material film is partially removed using the photoresist mask as a mask by etching with oxygen plasma. As a result, a portion of the two-dimensional material film remains under the photoresist mask. This portion of the two-dimensional material film becomes the two-dimensional material layer 1. Then, the resist mask is removed. This forms a two-dimensional material layer 1. The two-dimensional material layer 1 has the first part 1a, the second part 1b, and the third part 1c described above.

[0090] Next, the first electrode portion 5 is formed. In one example of this process, the first electrode portion 5 is formed by the aforementioned stripping method. First, a photoresist mask is formed on the first surface 2A using photolithography or EB drawing. An opening is formed in the photoresist mask in the area where the first electrode portion 5 is to be formed. Then, a film of metal or the like that which should become the first electrode portion 5 is formed on the photoresist mask. This film can be formed using vapor deposition, sputtering, or the like. At this time, the film is formed such that it extends from the inside of the opening of the photoresist mask to the upper surface of the photoresist mask. Then, by removing the photoresist mask along with a portion of the film, the remaining portion of the film disposed at the opening of the photoresist mask remains on the third portion 1c of the two-dimensional material layer 1, becoming the first electrode portion 5.

[0091] In other examples of this process, a metal film or the like, corresponding to the first electrode portion 5, is first formed on the first surface 2A. Then, a photoresist mask is formed on this film using photolithography. The photoresist mask is formed to cover the area where the first electrode portion 5 is to be formed, but not in areas other than the area where the first electrode portion 5 is to be formed. Then, the film is partially removed using wet etching and dry etching, with the photoresist mask acting as a mask. As a result, a portion of the film remains under the photoresist mask. This portion of the film becomes the first electrode portion 5. Then, the photoresist mask is removed. In this way, the first electrode portion 5 can also be formed.

[0092] In this process, it is preferable to form a protective film for the first portion 1a and the second portion 1b of the two-dimensional material layer 1 before the film to be formed into the first electrode portion 5. By forming the protective film in advance before film formation, process damage to the first portion 1a and the second portion 1b during film formation can be reduced.

[0093] Through the above procedures, we can obtain Figure 1 as well as Figure 2 The electromagnetic wave detector 100 shown is shown.

[0094] Operating principle of electromagnetic wave detectors

[0095] Next, the operating principle of the electromagnetic wave detector involved in this embodiment will be explained.

[0096] First, such as Figure 1As shown, a power supply circuit for applying a voltage V is electrically connected between the first electrode portion 5 and the second electrode portion 6. The first electrode portion 5, the two-dimensional material layer 1, the semiconductor layer 2, and the second electrode portion 6 are sequentially electrically connected. Next, a voltage V is applied between the first electrode portion 5 and the second electrode portion 6. Preferably, the voltage V is set in a manner that reverses the Schottky junction of the two-dimensional material layer 1 and the semiconductor layer 2. By applying the voltage V, a current I flows through the two-dimensional material layer 1, which becomes part of the current path between the first electrode portion 5 and the second electrode portion 6. A galvanometer (not shown) is provided in the power supply circuit to monitor the current I flowing through the two-dimensional material layer 1.

[0097] Next, when electromagnetic waves of the detection wavelength are irradiated onto the electromagnetic wave detector 100 from the plasma filter 3 side, surface plasmon resonance is generated in the plasma filter 3. When surface plasmon resonance is generated, the electromagnetic field at the resonance wavelength is enhanced, thereby enhancing the transmittance. The transmittance can reach approximately 100%. Furthermore, in the region where the outer periphery of each through-hole 30 of the plasma filter 3 contacts the first surface 2A of the semiconductor layer 2, the electromagnetic field is enhanced from several times to tens of times or more compared to the case where the incident electromagnetic field is set to 1. Thus, the electromagnetic field is enhanced in the peripheral region of the contact interface between the semiconductor layer 2 and the plasma filter 3, thereby improving the quantum efficiency in the semiconductor layer 2.

[0098] As a result, through the plasma filter 3, electromagnetic waves of only the detection wavelength are selectively incident on the semiconductor layer 2 and the quantum efficiency in the semiconductor layer 2 is improved, so a large number of photocarriers (electron-hole pairs) are generated in the semiconductor layer 2 through photoelectric conversion.

[0099] Photocarriers are injected with a voltage V into the first portion 1a of the two-dimensional material layer 1, causing a change in current I. The current component that causes this change in current I due to electromagnetic wave irradiation is called the photocurrent. Furthermore, the photocarriers generated in the semiconductor layer 2 provide an electric field effect to the second portion 1b of the two-dimensional material layer 1 via portion 4a of the insulating layer 4. As a result, the resistance of the second portion 1b of the two-dimensional material layer 1 changes, and the current I flowing through the two-dimensional material layer 1 changes. This effect is called the photoblocking effect.

[0100] In the electromagnetic wave detector 100, the photocurrent is amplified through the optical shutter effect, thereby causing a significant change in the current I. By detecting the change in current I, the electromagnetic wave detector 100 can detect electromagnetic waves of the detection wavelength.

[0101] Here, the electromagnetic wave detector involved in this embodiment is not limited to the structure for detecting changes in current in the two-dimensional material layer 1 as described above. For example, a constant current may flow between the first electrode portion 5 and the second electrode portion 6 to detect changes in voltage V between the first electrode portion 5 and the second electrode portion 6 (i.e., changes in voltage value in the two-dimensional material layer 1).

[0102] Alternatively, two or more identical electromagnetic wave detectors can be used to detect electromagnetic waves. For example, two or more identical electromagnetic wave detectors can be prepared. One detector can be placed in a shielded space that does not emit electromagnetic waves. The other detectors can be placed in a space that emits the electromagnetic waves that are being measured. Furthermore, the difference between the current I or voltage V of the detector emitting the electromagnetic waves and the detector placed in the shielded space can be measured. In this way, electromagnetic waves can also be detected.

[0103] <Effects>

[0104] The electromagnetic wave detector 100 according to this embodiment includes multiple photoelectric conversion elements and a plasma filter 3. Multiple through-holes 30 are periodically formed in the plasma filter 3. Each photoelectric conversion element mainly includes a semiconductor layer 2, an insulating layer 4, a two-dimensional material layer 1, a first electrode portion 5, and a second electrode portion 6. The semiconductor layer 2 has a region 20 that overlaps with one through-hole 30 when viewed from above. The insulating layer 4 is formed to cover a portion of the region 20. The two-dimensional material layer 1 is disposed on the other portion of the region 20 and the insulating layer 4, and is electrically connected to the other portion of the region 20. The first electrode portion 5 is electrically connected to the two-dimensional material layer 1. The second electrode portion 6 is electrically connected to the semiconductor layer 2.

[0105] In the electromagnetic wave detector 100, electromagnetic waves transmitted only through the plasma filter 3 are incident on the semiconductor layer 2 of multiple photoelectric conversion elements. As described above, the plasma filter 3 allows only electromagnetic waves of a specific wavelength to be transmitted, thereby improving the quantum efficiency of the semiconductor layer 2 at that wavelength. Therefore, compared to the detector described in Patent Document 1, the electromagnetic wave detector 100 can selectively detect only electromagnetic waves of a specific wavelength band with high precision.

[0106] Furthermore, in the electromagnetic wave detector 100, the photoelectric conversion element includes a two-dimensional material layer 1 disposed on another portion of the region 20 overlapping with the plurality of through-holes of the plasma filter 3 and on the insulating layer 4, and electrically connected to the aforementioned other portion of the region 20. Therefore, as described above, in the electromagnetic wave detector 100, the photocurrent is amplified by the photoblocking effect. The photoblocking effect does not directly enhance the quantum efficiency of the photoelectric conversion material, but rather increases the current change caused by the incident electromagnetic wave; therefore, the quantum efficiency, equivalently calculated based on the differential current caused by the incident electromagnetic wave, can exceed 100%.

[0107] Therefore, the change in current I when the electromagnetic wave detector 100 is exposed to the aforementioned electromagnetic wave is greater than the change in current when the detector described in Patent Document 1 is exposed to the aforementioned electromagnetic wave, which does not exhibit the aforementioned shutter effect. Therefore, the electromagnetic wave detector 100 has higher sensitivity than the detector described in Patent Document 1.

[0108] In the case where the two-dimensional material layer 1 is, for example, a single layer of graphene, the thickness of the two-dimensional material layer 1 can ultimately be as thin as one atomic layer. Furthermore, the carrier mobility in single-layer graphene is greater than that in conventional semiconductor materials. Therefore, in the two-dimensional material layer 1, compared to conventional semiconductor materials, a small potential change generates a larger current change. For example, a potential change applied to the two-dimensional material layer 1 by a change in the electric field of the semiconductor layer 2 results in a current change greater than that in a typical semiconductor. Specifically, when calculated based on the electron mobility and thickness of the two-dimensional material layer 1, the aforementioned current change in the two-dimensional material layer 1 is several hundred to several thousand times greater than that in a typical semiconductor. Such an electromagnetic wave detector 100 has higher sensitivity than an electromagnetic wave detector that only detects photocarriers generated in the semiconductor layer 2.

[0109] Furthermore, in the electromagnetic wave detector 100, the two-dimensional material layer 1 is electrically connected to the other portion of the semiconductor layer 2 at the aforementioned opening, specifically, it is Schottky bonded to the semiconductor layer 2. The Schottky bond between the two-dimensional material layer 1 and the semiconductor layer 2 prevents current from flowing when a reverse bias is applied, enabling the electromagnetic wave detector 100 to perform a shutdown operation.

[0110] Furthermore, in the electromagnetic wave detector 100, one end of the two-dimensional material layer 1 along its length is disposed within the region 20 of the semiconductor layer 2. Therefore, the contact state between the two-dimensional material layer 1 and the semiconductor layer 2 becomes better, and the contact interface between the two-dimensional material layer 1 and the semiconductor layer 2 is less likely to hinder the movement of photocarriers generated by electromagnetic wave irradiation. As a result, the performance of the electromagnetic wave detector 100 is improved. Moreover, since the photoblocking effect dominates as the effect amplifying photoelectric flux, the sensitivity of the electromagnetic wave detector 100 does not significantly depend on the contact area between the two-dimensional material layer 1 and the semiconductor layer 2. Therefore, when using the photoblocking effect, the pixel area can be reduced, and the pixel can be miniaturized. On the other hand, the sensitivity of a typical quantum infrared sensor inevitably decreases when the pixel area is reduced. Therefore, reducing dark current is also difficult.

[0111] Implementation method 2.

[0112] like Figure 4 As shown, the electromagnetic wave detector 101 according to Embodiment 2 has a structure that is basically the same as that of the electromagnetic wave detector 100 according to Embodiment 1, and can achieve the same effect. However, it differs from the electromagnetic wave detector 100 in that the plasma filter 3 is disposed on the side opposite to the insulating layer 4, the two-dimensional material layer 1 and the first electrode portion 5 relative to the semiconductor layer 2.

[0113] like Figure 4 As shown, the insulating layer 4, the two-dimensional material layer 1, and the first electrode portion 5 are disposed on the first surface 2A of the semiconductor layer 2. The plasma filter 3 and the second electrode portion 6 are disposed on the second surface 2B of the semiconductor layer 2. The plasma filter 3 is disposed on the second electrode portion 6. The plasma filter 3 is disposed on the side opposite to the semiconductor layer 2, opposite to the second electrode portion 6. The material constituting the second electrode portion 6 is a conductive material that allows electromagnetic waves of the detection wavelength to be transmitted.

[0114] The first surface 2A of regions other than the multiple regions 20 is in contact with the insulating layer 4. The first surface 2A of each region 20 has: a first contact region, in contact with a first portion of the two-dimensional material layer 1 (described later); a second contact region, in contact with a portion of the insulating layer 4; and a region exposed from the two-dimensional material layer 1 and the insulating layer 4 when viewed from above. The entire second surface 2B is in contact with the second electrode portion 6. The third surface 3A of the plasma filter 3 is in contact with the second electrode portion 6.

[0115] An insulating layer 4 is disposed on the first surface 2A of the semiconductor layer 2 without being separated from other components. A portion of the insulating layer 4 disposed in areas other than the plurality of regions 20 contacts the first surface 2A of the semiconductor layer 2. The insulating layer 4 excludes the portion disposed on the plasma filter 3 and is not formed in a stepped manner. A two-dimensional material layer 1 is disposed on the second contact area of ​​region 20 and on the insulating layer 4. A portion of the two-dimensional material layer 1 disposed in areas other than the plurality of regions 20 is disposed on the insulating layer 4 that contacts the first surface 2A of the semiconductor layer 2. The two-dimensional material layer 1 includes a first portion 1a disposed in the first contact area and a second portion 1b disposed on the insulating layer 4, formed in a stepped manner, but excludes the third portion disposed on the plasma filter 3. The two-dimensional material layer 1 has one step. The first electrode portion 5 is electrically connected to the second portion 1b of the two-dimensional material layer 1.

[0116] The manufacturing method of electromagnetic wave detector 101 has a structure that is basically the same as that of electromagnetic wave detector 100, but the process of forming plasma filter 3 is performed after the process of forming the second electrode portion 6 and before the process of removing the protective film protecting the first surface 2A.

[0117] In the electromagnetic wave detector 101, compared to the electromagnetic wave detector 100, the two-dimensional material layer 1 has fewer steps, thus improving manufacturing yield and detection performance. For example, when the material constituting the semiconductor layer 2 includes Si, the insulating layer 4 can be formed using a thermal oxide film of Si. In such an electromagnetic wave detector 101, compared to the electromagnetic wave detector 100 which has an insulating layer 4 formed by a CVD method, the surface of the thermal oxide film has fewer irregularities and less residual charge, so it does not hinder the mobility of the two-dimensional material layer 1, thus improving the mobility and performance of the electromagnetic wave detector 101.

[0118] <Variation Example>

[0119] like Figure 5 As shown, in the electromagnetic wave detector 102, a variant of the electromagnetic wave detector 101, the second electrode portion 6 is disposed on the first surface 2A of the semiconductor layer 2 in the same manner as the insulating layer 4, the two-dimensional material layer 1, and the first electrode portion 5. The plasma filter 3 is disposed opposite to the semiconductor layer 2 on the side opposite to the insulating layer 4, the two-dimensional material layer 1, the first electrode portion 5, and the second electrode portion 6. The second electrode portion 6 is in contact with the first surface 2A of the semiconductor layer 2. The second electrode portion 6 is in contact with, for example, the first surface 2A of each region other than the plurality of regions 20 and a portion of the plurality of regions 20.

[0120] Electromagnetic wave detector 102 has essentially the same structure as electromagnetic wave detector 101, so it can achieve the same effect as electromagnetic wave detector 101.

[0121] Implementation method 3.

[0122] like Figure 6 As shown, the electromagnetic wave detector 103 according to Embodiment 3 has a structure that is substantially the same as that of the electromagnetic wave detector 100 according to Embodiment 1, and can achieve the same effect. However, it differs from the electromagnetic wave detector 100 in that the material constituting a part of the surface of the plasma filter 3 includes the aforementioned plasma resonant material. In other words, the electromagnetic wave detector 103 differs from the electromagnetic wave detector 100 in that the plasma filter 3 includes a first component 10 made of plasma resonant material and a second component 11 not made of plasma resonant material.

[0123] The second component 11 is configured as a core material, for example. The second component 11 has a surface that contacts the first surface 2A of the semiconductor layer 2 and other surfaces. The first component 10 is configured as a covering material that covers the entirety of the other surfaces of the second component 11.

[0124] The material constituting the second component 11 may include, for example, a dielectric material. The material constituting the second component 11 may include, for example, at least one of silicon oxide and silicon nitride.

[0125] The manufacturing method of electromagnetic wave detector 103 has a structure that is basically the same as that of electromagnetic wave detector 100. However, in the process of forming plasma filter 3, the process of first forming a film on the second component 11 and then forming a film on the first component 10 is different from that of electromagnetic wave detector 100.

[0126] In this case, the process of forming the plasma filter 3 can be performed solely by the steps of forming a film on the second component 11, processing the second component 11, and forming a film on the first component 10. In other words, the process of forming the plasma filter 3 does not require processing the plasma resonance material. Generally speaking, the processing of dielectric materials is easier than the processing of plasma resonance materials. In addition, the cost of dielectric materials is generally lower than that of Au and Ag, etc.

[0127] Therefore, the manufacturing cost of electromagnetic wave detector 103 is lower than that of electromagnetic wave detector 100.

[0128] In addition, the electromagnetic wave detector 103 may have the same structure as the electromagnetic wave detector 101 or the electromagnetic wave detector 102, except that it includes a second component 11 that is not made of plasma resonance material.

[0129] Implementation method 4.

[0130] like Figure 7 As shown, the electromagnetic wave detector 104 according to Embodiment 4 is similar to the electromagnetic wave detector 103 according to Embodiment 3, but differs from the electromagnetic wave detector 100 in that the plasma filter 3 includes a first component 10 made of plasma resonant material and a second component 11 not made of plasma resonant material.

[0131] The electromagnetic wave detector 104 has a structure that is basically the same as that of the electromagnetic wave detector 103 and can achieve the same effect, but it differs from the electromagnetic wave detector 103 in that the first component 10 and the second component 11 are stacked along the axis of each of the plurality of through holes 30.

[0132] The plasma filter 3 is configured as a stack of two or more first components 10 and one or more second components 11. For example, the plasma filter 3 is configured with three or more first components 10 and two or more second components 11.

[0133] The material constituting the first component 10 is the aforementioned plasma resonance material. The material constituting the second component 11 is a dielectric material. The material constituting the second component 11 includes, for example, at least one of silicon oxide and silicon nitride.

[0134] The first component 10 and the second component 11 constitute a capacitor. This plasma filter 3 functions similarly to an open-loop resonator or a hyperbolic metamaterial at the detection wavelength, resulting in a negative or zero refractive index at that wavelength, thus producing a focusing or lensing effect. Consequently, the opening area of ​​each through-hole 30 in the electromagnetic wave detector 104 can be smaller than that in the electromagnetic wave detector 100. That is, the pixels of the electromagnetic wave detector 104 can be smaller than those of the electromagnetic wave detector 100. Therefore, when comparing electromagnetic wave detectors 104 and 100 with the same external dimensions, the electromagnetic wave detector 104 has more pixels and thus higher resolution than the electromagnetic wave detector 100.

[0135] In addition, the electromagnetic wave detector 104 may have the same structure as the electromagnetic wave detector 101 or the electromagnetic wave detector 102, except that it includes a first component 10 made of plasma resonance material and a second component 11 not made of plasma resonance material.

[0136] Implementation method 5.

[0137] The electromagnetic wave detector according to Embodiment 5 has essentially the same structure as the electromagnetic wave detector 100 according to Embodiment 1, and can achieve the same effect, but it is determined that... Figure 8 The plasma filter 3 shown has a plurality of through holes 30 with a period P equal to the detection wavelength, which is different from the electromagnetic wave detector 100.

[0138] In embodiment 5, the period P is set as the main parameter that determines the wavelength band selected by the plasma filter 3. When the detection wavelength is within the infrared wavelength band, the opening width and depth (thickness of the plasma filter 3) of each of the plurality of through holes 30 of the plasma filter 3 are approximately 1 / 4 of the detection wavelength.

[0139] In the aforementioned period P of the plurality of through holes 30, manufacturing deviations are unlikely to occur compared to the opening width and depth of each of the plurality of through holes 30. Therefore, in the electromagnetic wave detector according to Embodiment 5, compared to the electromagnetic wave detector 100, even if deviations occur in the opening width and depth of each of the plurality of through holes 30 of the plasma filter 3, the selection performance of the detection wavelength is unlikely to be affected by such deviations.

[0140] Furthermore, as mentioned above, the planar shape of each of the multiple through holes 30 can be any shape. For example... Figure 8 As shown, the planar shape of each of the multiple through holes 30 can also be, for example, a square shape.

[0141] Furthermore, the electromagnetic wave detector according to Embodiment 5 may also have the same structure as any of the electromagnetic wave detectors 101 to 104 according to Embodiments 2 to 4, except that the period P of the plurality of through holes 30 of the plasma filter 3 is equal to the detection wavelength.

[0142] Implementation method 6.

[0143] The electromagnetic wave detector according to Embodiment 6 has a structure that is substantially the same as that of the electromagnetic wave detector 100 according to Embodiment 1, and can achieve the same effect, but as Figure 9 as well as Figure 10 As shown, the planar shape of the plurality of through holes 30 is determined to have both length and width directions, which differs from that of the electromagnetic wave detector 100.

[0144] exist Figure 9 as well as Figure 10In the plasma filter 3 shown, the planar shape of each through-hole 30 is symmetrical only with respect to one imaginary straight line along the third surface 3A. In other words, the planar shape of each through-hole 30 has a length direction and a width direction. The length directions of each through-hole 30 are, for example, parallel to each other. The width directions of each through-hole 30 are, for example, parallel to each other.

[0145] In such a plasma filter 3, surface plasma resonance occurs only when an electromagnetic wave of the detection wavelength is irradiated and has an electric field orthogonal to the longitudinal direction of the planar shape of each through-hole 30. That is, Figure 9 as well as Figure 10 The plasma filter 3 shown has polarization selectivity. Therefore, an electromagnetic wave detector equipped with such a plasma filter 3 can detect only specific polarized light within the electromagnetic wave of the detection wavelength. Such an electromagnetic wave detector capable of detecting polarized light can distinguish between man-made and natural objects, such as oil floating on the sea surface, vehicles in the desert, or people and roads in summer. Furthermore, such an electromagnetic wave detector capable of detecting polarized light can also be used to determine the polarization characteristics of molecules, etc.

[0146] like Figure 10 As shown, the period P in the length direction of each through hole 30 may, for example, be equal to the period P in the width direction of each through hole 30. Alternatively, the period P in the length direction of each through hole 30 may, for example, be different from the period P in the width direction of each through hole 30. Furthermore, the arrangement of the plurality of through holes 30 in the width direction of each through hole 30 may also be asymmetrical.

[0147] Furthermore, the electromagnetic wave detector according to Embodiment 6 may also have the same structure as any of the electromagnetic wave detectors 101 to 104 according to Embodiments 2 to 5, except that the planar shape of each of the plurality of through holes 30 is determined to have aspects in the length direction and width direction.

[0148] Implementation method 7.

[0149] like Figure 11 As shown, the electromagnetic wave detector 105 according to Embodiment 6 has a structure that is basically the same as that of the electromagnetic wave detector 100 according to Embodiment 1, and can achieve the same effect. However, it differs from the electromagnetic wave detector 100 in that the inner peripheral surface 3C of each of the plurality of through holes 30 is inclined relative to the hole axis of each through hole 30.

[0150] like Figure 11As shown, the cross-sectional shape of the plasma filter 3 is, for example, a so-called conical shape. Each inner peripheral surface 3C of the plurality of through holes 30 forms an acute angle with respect to the third surface 3A and an obtuse angle with respect to the fourth surface 3B. The wavelength band, half-width, and Q-factor of the resonant wavelength are controlled according to the angle formed by the inner peripheral surface 3C with respect to the third surface 3A (hereinafter, the tilt angle).

[0151] Basically, the smaller the tilt angle mentioned above, the narrower the wavelength band of the electromagnetic waves transmitted by the plasma filter 3 becomes. As a result, Figure 11 The electromagnetic wave detector 105 shown is compared to Figure 1 The electromagnetic wave detector 100 shown has higher wavelength selectivity (monochromaticity) for electromagnetic waves, enabling it to detect electromagnetic waves of the detection wavelength with higher precision.

[0152] Furthermore, the cross-sectional shape of the plasma filter 3 can also be, for example, a so-called inverted conical shape. The inner peripheral surfaces 3C of each of the plurality of through holes 30 can also form obtuse angles relative to the third surface 3A and acute angles relative to the fourth surface 3B. Basically, the larger the aforementioned tilt angle, the wider the wavelength band of the electromagnetic waves transmitted by the plasma filter 3 becomes.

[0153] Furthermore, the contribution of the aforementioned tilt angle to the wavelength band varies depending on whether the periodicity of the multiple through holes 30 is one-dimensional or two-dimensional, and the shape of each plane of the multiple through holes 30.

[0154] The electromagnetic wave detector according to Embodiment 7 may also have the same structure as any of the electromagnetic wave detectors 101 to 104 according to Embodiments 2 to 6, except that the planar shape of each of the plurality of through holes 30 is determined to have the aspect of the length direction and the width direction.

[0155] Implementation method 8.

[0156] like Figure 12 as well as Figure 13 As shown, the electromagnetic wave detector 106 according to Embodiment 8 has a structure that is substantially the same as that of the electromagnetic wave detector 100 according to Embodiment 1 and has the same effect, but it differs from the electromagnetic wave detector 100 in that the end of the two-dimensional material layer 1 in the length direction is disposed on the insulating layer 4.

[0157] The longitudinal end of the two-dimensional material layer 1 is disposed, for example, on an insulating layer 4 disposed on the plasma filter 3. In this case, the two-dimensional material layer 1 has a first portion 1a and two or more second portions 1b and a third portion 1c disposed in a manner that sandwiches the first portion 1a. Alternatively, the longitudinal end of the two-dimensional material layer 1 may also be disposed, for example, on an insulating layer 4 disposed on region 20. In this case, the two-dimensional material layer 1 has a first portion 1a, a third portion 1c, and two or more second portions 1b disposed in a manner that sandwiches the first portion 1a.

[0158] The electromagnetic wave detector according to Embodiment 8 may also have the same structure as any of the electromagnetic wave detectors 101 to 105 according to Embodiments 2 to 7, except that the end of the two-dimensional material layer 1 in the length direction is disposed on the insulating layer 4.

[0159] Implementation method 9.

[0160] like Figure 14 As shown, the electromagnetic wave detector 107 according to Embodiment 9 has a structure that is basically the same as that of the electromagnetic wave detector 100 according to Embodiment 1 and has the same effect. However, it differs from the electromagnetic wave detector 100 in that a buffer layer 7 is disposed between the two-dimensional material layer 1 and the semiconductor layer 2 inside the through hole 30.

[0161] The buffer layer 7 electrically connects the first portion 1a of the two-dimensional material layer 1 and the region 20 of the semiconductor layer 2. Specifically, the buffer layer 7 is configured such that the first portion 1a of the two-dimensional material layer 1 and the aforementioned first contact region of the semiconductor layer 2 are electrically connected by the tunneling current. The material constituting the buffer layer 7 can be any material with electrical insulation properties, for example, including at least one material selected from the group consisting of SiO2, Si3N4, HfO2, Al2O3, and BN.

[0162] The buffer layer 7 may be disposed on at least the first contact area in region 20, but may be disposed on both the first and second contact areas. The buffer layer 7 may be disposed in such a way that a portion of region 20 is exposed.

[0163] For example, the thickness of the buffer layer 7 is set in such a way that a tunneling current can be generated between the two-dimensional material layer 1 and the semiconductor layer 2 when an electromagnetic wave of the detection wavelength is incident. Regarding the thickness of the buffer layer 7, for example, it is 1 nm or more and 10 nm or less. The thickness of the buffer layer 7 is determined according to the detection wavelength. The method for fabricating the buffer layer 7 can be any method, such as ALD (Atomic Layer Deposition), vacuum evaporation, or sputtering. Alternatively, the buffer layer 7 can also be formed by oxidizing or nitriding the surface of the semiconductor layer 2. Alternatively, the buffer layer 7 can also be a natural oxide film formed on the surface of the semiconductor layer 2.

[0164] In the electromagnetic wave detector 107, by utilizing the buffer layer 7 to suppress leakage current at the interface between the semiconductor layer 2 and the two-dimensional material layer 1, dark current can be reduced compared to the electromagnetic wave detector 100, which does not have the buffer layer 7. Furthermore, in the electromagnetic wave detector 107, by making the thickness of the buffer layer 7 such that it allows for tunneling injection from the semiconductor layer 2 into the two-dimensional material layer 1, a large photocurrent is injected into the two-dimensional material layer 1, resulting in high sensitivity.

[0165] Furthermore, the thickness of the buffer layer 7 can be thicker than the thickness capable of forming tunneling current between the two-dimensional material layer 1 and the semiconductor layer 2, but thinner than the thickness of the insulating layer 4. In this case, photocarriers generated in the semiconductor layer 2 are not injected into the two-dimensional material layer 1, only a photoblocking effect occurs. If the buffer layer 7 is thinner than the insulating layer 4, a carrier density gradient is generated between the two-dimensional material layer 1 in contact with the insulating layer 4 and the two-dimensional material layer 1 in contact with the buffer layer 7. As a result, the mobility of the two-dimensional material layer 1 increases, thus increasing the sensitivity.

[0166] The electromagnetic wave detector 107 according to Embodiment 9 may also have the same structure as any of the electromagnetic wave detectors 101 to 106 according to Embodiments 2 to 8, except that a buffer layer 7 is disposed between the two-dimensional material layer 1 and the semiconductor layer 2 inside each through hole 30.

[0167] Implementation method 10.

[0168] like Figure 15 As shown, the electromagnetic wave detector 108 according to Embodiment 10 has a structure that is basically the same as that of the electromagnetic wave detector 100 according to Embodiment 1 and has the same effect, but it is different from the electromagnetic wave detector 100 in that a connecting conductor 8 is disposed between the two-dimensional material layer 1 and the semiconductor layer 2 inside each through hole 30.

[0169] The connecting conductor 8 electrically connects the first portion 1a of the two-dimensional material layer 1 to the region 20 of the semiconductor layer 2. The first portion 1a of the two-dimensional material layer 1 is electrically connected to the aforementioned first contact region of the semiconductor layer 2 via the connecting conductor 8.

[0170] The connecting conductor 8 is preferably ohmically bonded to the semiconductor layer 2. Furthermore, the connecting conductor 8 preferably exhibits high transmittance at wavelengths of electromagnetic waves detected by the electromagnetic wave detector.

[0171] The connecting conductor 8 may be disposed on at least the first contact area in region 20, but may be disposed on both the first and second contact areas. The connecting conductor 8 may be disposed in such a way that a portion of region 20 is exposed, for example.

[0172] In the electromagnetic wave detector 108, by providing a connecting conductor 8 between the two-dimensional material layer 1 and the semiconductor layer 2, the contact resistance between the two-dimensional material layer 1 and the semiconductor layer 2 can be reduced compared to the electromagnetic wave detector 100, and the attenuation of photocurrent, which is a problem when the junction of the two-dimensional material layer 1 and the semiconductor layer 2 is a Schottky junction, can be suppressed.

[0173] Furthermore, in the electromagnetic wave detector 108, it is preferable that the thickness of the connecting conductor 8 and the thickness of the insulating layer 4 are substantially the same, that is, the position of the upper surface of the connecting conductor 8 is substantially the same as the position of the upper surface of the insulating layer 4. In this case, the two-dimensional material layer 1 is formed horizontally without bending, so the mobility of charge carriers in the two-dimensional material layer 1 is increased. The light shutter effect is proportional to the mobility, so the detection sensitivity of the electromagnetic wave detector is improved.

[0174] The electromagnetic wave detector 108 according to Embodiment 10 may also have the same structure as any of the electromagnetic wave detectors 101 to 106 according to Embodiments 2 to 8, except that a connecting conductor 8 is formed inside each through hole 30.

[0175] Implementation method 11.

[0176] like Figure 16 As shown, the electromagnetic wave detector 109 according to Embodiment 11 has a structure that is substantially the same as that of the electromagnetic wave detector 100 according to Embodiment 1 and achieves the same effect, but it differs from the electromagnetic wave detector 100 in that the semiconductor layer 2 includes a first semiconductor portion 21 having a first conductivity type and a second semiconductor portion 22 having a second conductivity type bonded to the first semiconductor portion 21, and the bonding interface of the first semiconductor portion 21 and the second semiconductor portion 22 is disposed in each region 20.

[0177] The first semiconductor portion 21 and the second semiconductor portion 22 are arranged along the first surface 2A. The first semiconductor portion 21 is doped with the opposite carrier type to that of the second semiconductor portion 22. That is, the first semiconductor portion 21 and the second semiconductor portion 22 are pn-junctioned. At least a portion of the pn junction interface 23 of the first semiconductor portion 21, the second semiconductor portion 22, and the second semiconductor portion 22 is disposed within the region 20.

[0178] The materials constituting the first semiconductor portion 21 and the second semiconductor portion 22 are, for example, the same semiconductor material.

[0179] like Figure 16 As shown, the pn junction interface 23 of the first semiconductor portion 21 and the second semiconductor portion 22 is configured to contact the first portion 1a of the two-dimensional material layer 1. Therefore, when electromagnetic waves are irradiated, photocarriers generated at the pn junction interface 23 of the first semiconductor portion 21 and the second semiconductor portion 22 can be easily extracted to the two-dimensional material layer 1. Furthermore, the conductivity of the two-dimensional material layer 1 on the pn junction interface 23 changes due to the change in the local electric field at the pn junction generated by the photocarriers. As a result, the detection sensitivity of the electromagnetic wave detector is improved.

[0180] Furthermore, the materials constituting the first semiconductor portion 21 and the second semiconductor portion 22 can also be different semiconductor materials. In this case, if the electromagnetic wave detector 109 also includes a plasma filter 3 arranged in a manner that allows for the presence of multiple resonant wavelengths, then the electromagnetic wave detector 109 can detect multiple and narrow wavelength bands of electromagnetic waves.

[0181] The electromagnetic wave detector 109 according to Embodiment 11 may also have the same structure as any of the electromagnetic wave detectors 101 to 108 according to Embodiments 2 to 9, except that a connecting conductor 8 is formed inside each through hole 30.

[0182] Implementation method 12.

[0183] like Figure 17 as well as Figure 18 As shown, the electromagnetic wave detector 110 according to Embodiment 12 has a structure that is substantially the same as that of the electromagnetic wave detector 100 according to Embodiment 1, and achieves the same effect, but differs from the electromagnetic wave detector 100 in that the two-dimensional material layer 1 is electrically connected to the first contact regions of each of the plurality of regions 20. Furthermore, in Figure 18 In this design, the electrical wiring connecting the first electrode section 5 and the second electrode section 6 is omitted.

[0184] A two-dimensional material layer 1 may be electrically connected to two adjacent regions 20, for example. Alternatively, a two-dimensional material layer 1 may be electrically connected to three or more adjacent regions 20.

[0185] In addition, Figure 18 In the insulating layer 4 shown, only the portion facing one side of the through hole 30 is stepped, but it is also possible that both the portion of the insulating layer 4 facing one side of the through hole 30 and the portion facing the other side are stepped. From different viewpoints, in Figure 18 In the two-dimensional material layer 1 shown, the number of steps in the portion of the through hole 30 located on one side is greater than the number of steps in the portion located on the other side, but the number of steps in the portion of the two-dimensional material layer 1 located on one side and the portion located on the other side relative to the through hole 30 can also be equal.

[0186] In electromagnetic wave detector 110, compared to electromagnetic wave detector 100, there are more regions 20 electrically connected to a two-dimensional material layer 1, so the amount of photocarriers received by a two-dimensional material layer 1 from the semiconductor layer 2 increases. As a result, the sensitivity of electromagnetic wave detector 110 is higher than that of electromagnetic wave detector 100.

[0187] The electromagnetic wave detector 110 according to Embodiment 12 may also have the same structure as any of the electromagnetic wave detectors 101 to 109 according to Embodiments 2 to 10, except that the two-dimensional material layer 1 is electrically connected to the first contact area of ​​each of the plurality of regions 20.

[0188] Implementation method 13.

[0189] like Figure 19 as well as Figure 20 As shown, the electromagnetic wave detector 111 according to Embodiment 13 has a structure that is basically the same as that of the electromagnetic wave detector 100 according to Embodiment 1, and has the same effect, but the structure of the first electrode portion 5 and the insulating layer 4 is different from that of the electromagnetic wave detector 100.

[0190] In the electromagnetic wave detector 111, an insulating layer 4 and a first electrode portion 5 are formed in a ring shape, and the first portion of the two-dimensional material layer 1 is disposed further inside than the insulating layer 4 and the first electrode portion 5.

[0191] In the electromagnetic wave detector 111, compared to the electromagnetic wave detector 100, the photocurrent extracted from the semiconductor layer 2 via the two-dimensional material layer 1 is increased, so the detection sensitivity is higher.

[0192] In addition, Figure 19 as well as Figure 20In the process, the third part 1c of the two-dimensional material layer 1 is disposed on the first electrode part 5, but the third part 1c of the two-dimensional material layer 1 may also be disposed below the first electrode part 5.

[0193] <Variation Example>

[0194] like Figure 21 As shown, in the electromagnetic wave detector 112, a modified example of the electromagnetic wave detector 111, the two-dimensional material layer 1 is electrically connected to a portion of the first electrode portion 5 on one side where the opposing through-hole 30 is located, and is electrically connected to another portion of the first electrode portion 5 on the other side where the opposing through-hole 30 is located.

[0195] Electromagnetic wave detector 112 has essentially the same structure as electromagnetic wave detector 111, so it can achieve the same effect as electromagnetic wave detector 111.

[0196] Furthermore, in both electromagnetic wave detectors 111 and 112, the planar shape of the first electrode portion 5 can also be C-shaped. In other words, when viewed from above, the ends of the first electrode portions 5 can be spaced apart in the circumferential direction of the through hole 30. Additionally, when viewed from above, the ends of the first electrode portions 5 can also be spaced apart in the radial direction of the through hole 30.

[0197] The electromagnetic wave detectors 111 and 112 according to Embodiment 13 may have the same structure as any of the electromagnetic wave detectors 101 to 110 according to Embodiments 2 to 12, except that the insulating layer 4 and the first electrode portion 5 are formed in a ring.

[0198] Implementation method 14.

[0199] like Figure 22 As shown, the electromagnetic wave detector 113 according to Embodiment 14 has a structure that is basically the same as that of the electromagnetic wave detector 100 according to Embodiment 1, and can achieve the same effect, but it is different from the electromagnetic wave detector 100 in that the thickness of the insulating layer 4 changes as it approaches the first electrode portion 5 from the region 20.

[0200] like Figure 22 As shown, the thickness of the insulating layer 4 increases as it approaches the first electrode portion 5 from region 20. The insulating layer 4 has an inclined surface 4C that is inclined relative to the first surface 2A of the semiconductor layer 2. The inclination angle between the inclined surface 4C and the first surface 2A is an acute angle. At least a portion of the inclined surface 4C is disposed on region 20.

[0201] Two-dimensional material layer 1 extends on inclined surface 4C. Specifically, the second part 1b of two-dimensional material layer 1 is disposed on inclined surface 4C.

[0202] The insulating layer 4 with the tilted surface 4C can be formed by any method. For example, the insulating film can be formed by tilting the semiconductor layer 2 to form the insulating layer 4 with the tilted surface 4C. Alternatively, the insulating layer 4 with the tilted surface 4C can be formed by dry etching the insulating layer 4 pre-formed on the semiconductor layer 2 while the semiconductor layer 2 is tilted.

[0203] In the electromagnetic wave detector 113, a gradient is set in the thickness of the insulating layer 4, thereby producing a localized variation in the degree of electric field change in the two-dimensional material layer 1 when electromagnetic waves are irradiated onto the semiconductor layer 2. That is, when electromagnetic waves irradiate the semiconductor layer 2, providing a change in the electric field to the two-dimensional material layer 1, the degree of this electric field change varies locally according to the variation in the thickness of the insulating layer 4. As a result, the mobility of charge carriers in the two-dimensional material layer 1 is increased, and the detection sensitivity of the electromagnetic wave detector is improved.

[0204] The electromagnetic wave detector 113 according to embodiment 14 may also have the same structure as any of the electromagnetic wave detectors 101 to 112 according to embodiments 2 to 13, except that the thickness of the insulating layer 4 changes as it approaches the first electrode portion 5 from region 20.

[0205] Implementation method 15.

[0206] like Figure 23 As shown, the electromagnetic wave detector 114 according to Embodiment 15 has a structure that is substantially the same as that of the electromagnetic wave detector 100 according to Embodiment 1, and can achieve the same effect, but it differs from the electromagnetic wave detector 100 in that a gap V is formed between the semiconductor layer 2 and the two-dimensional material layer 1.

[0207] The first portion 1a of the two-dimensional material layer 1, which functions as the source region in the opto-block effect, is electrically connected to the aforementioned first contact region of the semiconductor layer 2 via the connecting conductor 8. The thickness of the connecting conductor 8 is preferably equal to the sum of the thickness of the plasma filter 3 and the thickness of the insulating layer 4. In this case, the two-dimensional material layer 1 extends planarly from the connecting conductor 8 onto the insulating layer 4. Furthermore, the aforementioned first contact region of the semiconductor layer 2 does not contact the two-dimensional material layer 1, but rather contacts the connecting conductor 8.

[0208] The second portion 1b of the two-dimensional material layer 1, which functions as the source region in the photoblocking effect, has a portion facing the gap V and a portion connected to the insulating layer 4. In this case, photocarriers generated in the semiconductor layer 2 when an incident electromagnetic wave occurs provide an electric field effect to the second portion 1b of the two-dimensional material layer 1 via the portion 4a of the insulating layer 4 or the gap V. That is, a photoblocking effect is also generated in this structure. Since the two-dimensional material layer 1 and the semiconductor layer 2 are not directly connected, the mobility of the two-dimensional material layer 1 does not decrease. Therefore, its performance as an electromagnetic wave detector is also improved.

[0209] <Variation Example>

[0210] like Figure 24 As shown, in the electromagnetic wave detector 115, a variant of the electromagnetic wave detector 114, the semiconductor layer 2 has a protrusion 24. The protrusion 24 is disposed inside the through-hole 30 of the plasma filter 3, i.e., on region 20. The two-dimensional material layer 1 is in contact with the protrusion 24. The protrusion 24 has the aforementioned first contact region in the semiconductor layer 2 that contacts a first portion of the two-dimensional material layer 1. The height of the protrusion 24 is preferably as follows: Figure 24 The thickness shown is equal to the sum of the thickness of the plasma filter 3 and the thickness of the insulating layer 4. Furthermore, in the process of preparing the semiconductor layer 2 in the above manufacturing method, the bump 24 can be formed by processing the semiconductor layer 2 using photolithography and dry etching. The plasma filter 3 can be formed on the semiconductor layer 2 on which the bump 24 is formed.

[0211] A light shutter effect also occurs in this structure. Furthermore, in the void V portion, the two-dimensional material layer 1 and the insulating layer 4 are not directly connected, so the mobility of the two-dimensional material layer 1 does not decrease. Therefore, its performance as an electromagnetic wave detector is also improved.

[0212] The electromagnetic wave detectors 114 and 115 according to Embodiment 15 may have the same structure as any of the electromagnetic wave detectors 101 to 113 according to Embodiments 2 to 14, except that a gap V is formed between the semiconductor layer 2 and the two-dimensional material layer 1.

[0213] Implementation method 16.

[0214] like Figure 25 As shown, the electromagnetic wave detector 116 according to Embodiment 16 has a structure that is substantially the same as that of the electromagnetic wave detector 100 according to Embodiment 1, and can achieve the same effect, but it differs from the electromagnetic wave detector 100 in that it also has at least one or more contact layers 9 that are in contact with the two-dimensional material layer 1.

[0215] Contact layer 9 is disposed, for example, on two-dimensional material layer 1. Contact layer 9 is made of a material that can supply holes or electrons to two-dimensional material layer 1 through contact with it. Holes or electrons can be arbitrarily doped into two-dimensional material layer 1 through contact layer 9.

[0216] For example, a composition containing a photosensitizer having a benzoquinone diazinol group and a phenolic varnish resin, known as a positive photoresist, can be used as the contact layer 9. Alternatively, materials having polar groups can be used as the materials constituting the contact layer 9. For example, materials having electron-withdrawing groups, as an example of such materials, have the effect of reducing the electron density of the two-dimensional material layer 1. Conversely, materials having electron-donating groups, as an example of such materials, have the effect of increasing the electron density of the two-dimensional material layer 1. Examples of materials having electron-withdrawing groups include those having halogen, nitrile, carboxyl, or carbonyl groups. Examples of materials having electron-donating groups include those having alkyl, ethanol, amino, or hydroxyl groups. In addition to the above, materials that generate a charge shift in the molecular whole through polar groups can also be used as the materials for the contact layer 9.

[0217] Furthermore, any material that generates polarity by inducing charge shifts within molecules, including organic materials, metals, semiconductors, insulators, two-dimensional materials, or any mixtures thereof, can be used as the material for contact layer 9. Here, when contact layer 9, composed of an inorganic material, is in contact with two-dimensional material layer 1, the conductivity type of the doped two-dimensional material layer 1 is p-type if the work function of contact layer 9 is greater than that of two-dimensional material layer 1, and n-type if the work function of contact layer 9 is less than that of two-dimensional material layer 1. In contrast, when contact layer 9 is an organic material, the organic material constituting contact layer 9 does not have a definite work function. Therefore, regarding whether two-dimensional material layer 1 is n-type or p-type doped, it is preferable to determine the polarity of the material of contact layer 9 by the polarity of the molecules of the organic material used in contact layer 9.

[0218] For example, when a composition containing a photosensitive agent with a benzoquinone diazine group and a phenolic varnish resin, known as a positive photoresist, is used as the contact layer 9, the area in the two-dimensional material layer 1 where the photoresist is formed by photolithography becomes a p-type two-dimensional material layer area. Therefore, the mask formation process that contacts the surface of the two-dimensional material layer 1 becomes unnecessary. As a result, process damage to the two-dimensional material layer 1 can be reduced and the process simplified.

[0219] The electromagnetic wave detector 116 also includes a contact layer 9 that contacts the two-dimensional material layer 1. As described above, by using a material with electron-withdrawing or electron-donating groups as the material of the contact layer 9, the state (conductivity type) of the two-dimensional material layer 1 can be intentionally made to be n-type or p-type. In this case, the influence of carrier doping from the first electrode portion 5 and the semiconductor layer 2 can be considered, and the carrier doping of the two-dimensional material layer 1 can be controlled. As a result, the performance of the electromagnetic wave detector can be improved.

[0220] Furthermore, by forming a contact layer 9 only on either the first electrode portion 5 side or the semiconductor layer 2 side of the upper surface of the two-dimensional material layer 1, a charge density gradient is formed in the two-dimensional material layer 1. As a result, the mobility of charge carriers in the two-dimensional material layer 1 is improved, enabling higher sensitivity of the electromagnetic wave detector.

[0221] Alternatively, multiple contact layers 9 can be formed on the two-dimensional material layer 1. The number of contact layers 9 can be three or more, and can be set to any number. Multiple contact layers 9 can also be formed on the two-dimensional material layer 1 located between the first electrode portion 5 and the semiconductor layer 2. In this case, the materials of the multiple contact layers 9 can be the same material or different materials.

[0222] Furthermore, in the electromagnetic wave detector 116, the thickness of the contact layer 9 is preferably sufficiently thin to allow for photoelectric conversion when the two-dimensional material layer 1 is irradiated with electromagnetic waves. On the other hand, it is preferable to form the contact layer 9 with a thickness sufficient to dope carriers into the two-dimensional material layer 1 from the contact layer 9. Regarding the contact layer 9, any structure can be adopted as long as it allows for the introduction of carriers such as molecules or electrons into the two-dimensional material layer 1. For example, it is also possible to immerse the two-dimensional material layer 1 in a solution and supply carriers to the two-dimensional material layer 1 at the molecular level, without forming a solid contact layer 9 on the two-dimensional material layer 1, and instead dope the two-dimensional material layer 1 with carriers.

[0223] In addition to the materials described above, materials that generate polarity reversal can also be used as the material for contact layer 9. In this case, if the polarity of contact layer 9 changes, electrons or holes generated during the reversal are supplied to the two-dimensional material layer 1. Therefore, electron or hole doping occurs in the portion of the two-dimensional material layer 1 that is in contact with contact layer 9. Therefore, even if contact layer 9 is removed, that portion of the two-dimensional material layer 1 that is in contact with contact layer 9 remains doped with electrons or holes as is. Therefore, when a material that generates polarity reversal is used as contact layer 9, contact layer 9 can be removed from the two-dimensional material layer 1 after a certain period of time. In this case, the opening area of ​​the two-dimensional material layer 1 increases compared to the case where contact layer 9 is present. Therefore, the detection sensitivity of the electromagnetic wave detector can be improved. Here, polarity reversal refers to the phenomenon of chemical transformation of polar groups, such as electron-withdrawing groups changing to electron-donating groups or electron-donating groups changing to electron-withdrawing groups or polar groups changing to non-polar groups or non-polar groups changing to polar groups.

[0224] Alternatively, the contact layer 9 can be formed of a material whose polarity changes upon irradiation by electromagnetic waves. In this case, by selecting a material that produces a polarity change at a specific wavelength of electromagnetic waves as the material of the contact layer 9, it is possible to dope the two-dimensional material layer 1 by generating a polarity change in the contact layer 9 only when irradiated by electromagnetic waves at a specific wavelength of electromagnetic waves. As a result, the photocurrent flowing into the two-dimensional material layer 1 can be increased.

[0225] Alternatively, a material that undergoes a redox reaction when irradiated by electromagnetic waves can be used as the material for the contact layer 9. In this case, electrons or holes generated during the redox reaction can be doped into the two-dimensional material layer 1.

[0226] The electromagnetic wave detector 116 according to embodiment 16 may also have the same structure as any of the electromagnetic wave detectors 101 to 115 according to embodiments 2 to 15, except that it also has at least one contact layer 9 that contacts the two-dimensional material layer 1.

[0227] Implementation method 17.

[0228] The electromagnetic wave detector according to Embodiment 17 has a structure that is substantially the same as that according to Embodiment 1 and has the same effect, but it differs from the electromagnetic wave detector 100 in that the two-dimensional material layer 1 includes a disordered layer structure portion.

[0229] In the electromagnetic wave detector of this embodiment, the region corresponding to the channel region in the two-dimensional material layer 1 is called a disordered layer structure portion. Here, disordered layer structure means a structure in which multiple graphene layers are stacked and the lattices of the stacked graphene layers are stacked in a mismatched state. Furthermore, the entire two-dimensional material layer 1 may be a disordered layer structure, or only a portion of it may be a disordered layer structure.

[0230] Any method can be used to fabricate the disordered layer structure. For example, the disordered layer structure can be formed by repeatedly transferring a single layer of graphene fabricated by CVD and stacking multiple layers of graphene. Alternatively, the disordered layer structure can be formed by growing graphene on graphene using ethanol or methane as a carbon source via CVD. By making the contact region between the two-dimensional material layer 1 and the insulating layer 4 a disordered layer structure, the carrier mobility in the two-dimensional material layer 1 is improved. Here, the conventional stacked graphene is called an AB stack, where the stacked graphene layers are stacked in a state of lattice matching. However, the graphene fabricated by CVD is polycrystalline, and when graphene is repeatedly transferred onto the graphene or when graphene is stacked on a substrate using CVD, the stacked graphene layers become disordered, resulting in a state of lattice mismatch.

[0231] The interlayer interactions in randomly layered graphene are less affected, and it possesses properties similar to those of monolayer graphene. Furthermore, the mobility of the two-dimensional material layer 1 decreases due to carrier scattering from the insulating layer 4, which serves as the substrate. However, while the graphene in contact with the insulating layer 4 in the randomly layered graphene is affected by carrier scattering, the upper layer of graphene stacked in a randomly layered configuration is less affected by carrier scattering from the insulating layer 4. Additionally, the interlayer interactions are less affected in the randomly layered graphene, thus increasing conductivity. Based on these findings, carrier mobility can be improved in randomly layered graphene. Consequently, the sensitivity of electromagnetic wave detectors can be enhanced.

[0232] Alternatively, the randomly layered graphene can be applied only to the portion of the two-dimensional material layer 1 present on the insulating layer 4. For example, graphene that is not randomly layered, such as monolayer graphene, can be used in the contact regions of the two-dimensional material layer 1 with the semiconductor layer 2 and with the first electrode portion 5. In this case, it is not necessary to increase the contact resistance between the first electrode portion 5 and the semiconductor layer 2 and the two-dimensional material layer 1, and the effect of carrier scattering on the insulating layer 4 of the two-dimensional material layer 1 can be suppressed.

[0233] The electromagnetic wave detector according to embodiment 17 may also have the same structure as any of the electromagnetic wave detectors 101 to 116 according to embodiments 2 to 16, except that the two-dimensional material layer 1 includes a disordered layer structure portion.

[0234] Implementation method 18.

[0235] The electromagnetic wave detector according to Embodiment 18 has a structure that is substantially the same as that of the electromagnetic wave detector 100 according to Embodiment 1, and has the same effect. However, it differs from the electromagnetic wave detector 100 in that the material constituting at least one of the semiconductor layer 2, the insulating layer 4 and the contact layer 9 is determined to be a material whose properties change by electromagnetic wave irradiation to provide a potential change to the two-dimensional material layer 1.

[0236] Alternatively, the materials constituting the semiconductor layer 2, insulating layer 4, and contact layer 9 may each be materials whose properties change with electromagnetic wave irradiation, thus providing a change in potential to the two-dimensional material layer 1. Alternatively, only any one of the materials constituting the semiconductor layer 2, insulating layer 4, and contact layer 9 may be materials whose properties change with electromagnetic wave irradiation, thus providing a change in potential to the two-dimensional material layer 1. Alternatively, only two of the materials constituting the semiconductor layer 2, insulating layer 4, and contact layer 9 may be materials whose properties change with electromagnetic wave irradiation, thus providing a change in potential to the two-dimensional material layer 1.

[0237] Semiconductor layer 2 may be composed of at least one material selected from the group consisting of semiconductor materials, pn junction materials, metal-semiconductor junction materials, metal-insulator-semiconductor junction materials, and perovskite materials (materials with a perovskite crystal structure).

[0238] The contact layer 9 is composed of at least one material selected from the group consisting of quantum dots, liquid crystal materials, fullerenes and perovskite materials.

[0239] The insulating layer 4 is composed of at least one of a ferroelectric material and a rare-earth oxide. For example, when a ferroelectric material with a polarization effect (pyroelectric effect) based on electromagnetic waves is used as the ferroelectric material, a change in polarization occurs in the ferroelectric material upon irradiation with electromagnetic waves. As a result, a change in potential can be provided to the two-dimensional material layer 1.

[0240] Furthermore, when the contact layer 9 is constructed of a material that provides a change in potential to the two-dimensional material layer 1 as described above, the contact layer 9 does not necessarily need to be in direct contact with the two-dimensional material layer 1. For example, the contact layer 9 may also be provided in a manner that contacts the upper or lower surface of the two-dimensional material layer 1 through an insulating film.

[0241] Furthermore, the electromagnetic wave detector according to Embodiment 18 may also have the same structure as any electromagnetic wave detector in Embodiments 2 to 17, except that the material constituting at least one of the semiconductor layer 2, the insulating layer 4 and the contact layer 9 is determined to be a material whose characteristics provide a change in potential to the two-dimensional material layer 1 through the change of electromagnetic wave irradiation.

[0242] Implementation method 19.

[0243] The electromagnetic wave detector according to Embodiment 19 has a structure that is substantially the same as that of the electromagnetic wave detector 100 according to Embodiment 1, and achieves the same effect, but differs from the electromagnetic wave detector 100 in that the cross-sectional shape of the inner peripheral surface 3C of each of the plurality of through holes 30 is a stepped shape. Figure 26 In this illustration, only the peripheral structure of one through-hole 30 of the plasma filter 3 of the electromagnetic wave detector according to Embodiment 19 is shown. The peripheral structures of other through-holes 30 and other components of the plasma filter 3 are omitted.

[0244] like Figure 26 As shown, the inner peripheral surface 3C has multiple (e.g., 2) stepped surfaces 3D and multiple (e.g., 3) plateau surfaces 3E. Each stepped surface 3D extends, for example, along the hole axis of the through hole 30. Each plateau surface 3E intersects the hole axis of the through hole 30 and has an annular shape when viewed from above. When viewed from above, the centers of each plateau surface 3E overlap, for example, with each other. When viewed from above, the centers of each plateau surface 3E overlap, for example, with the center of the through hole 30. Each plateau surface 3E is, for example, orthogonal to the hole axis of the through hole 30. The dimensions of each stepped surface 3D are, for example, equal to each other. The dimensions of each plateau surface 3E are, for example, equal to each other. In the radial direction relative to the center of each through hole 30, the upper end of the outermost stepped surface 3D (the uppermost stepped surface 3D) is connected to the inner peripheral end of the fourth surface 3B. The insulating layer 4 and the two-dimensional material layer 1 are disposed on the multiple stepped surfaces 3D, multiple plateau surfaces 3E, and the fourth surface 3B of the plasma filter 3.

[0245] At least one of the through holes 30 has Figure 26 The structure shown is sufficient, but for example, the multiple through holes 30 of the plasma filter 3 each have Figure 26 The structure shown.

[0246] In the electromagnetic wave detector according to embodiment 19, compared with the electromagnetic wave detector 100, when electromagnetic waves are irradiated onto the plasma filter 3, it is difficult to induce high-order diffraction in the plasma filter 3, so the intensity of the electromagnetic waves transmitted through the plasma filter 3 can be enhanced.

[0247] In cross-sectional view, each step surface 3D can also have a conical shape. In other words, each step surface 3D can also be inclined in such a way that the distance from the third surface 3A increases as it moves away from the center of the through hole 30.

[0248] The electromagnetic wave detector according to embodiment 19 may also have the same structure as any electromagnetic wave detector in embodiments 2 to 18, except that the cross-sectional shape of each inner peripheral surface 3C of the plurality of through holes 30 is stepped (step-shaped).

[0249] Implementation method 20.

[0250] The electromagnetic wave detector according to Embodiment 20 has a structure that is basically the same as that of the electromagnetic wave detector 100 according to Embodiment 1 and has the same effect, but it is different from the electromagnetic wave detector 100 in that a plurality of grooves 31 surrounding a through hole 30 are formed on the fourth surface 3B of the plasma filter 3. Figure 27 as well as Figure 28 Only the peripheral structure of one through-hole 30 of the plasma filter 3 of the electromagnetic wave detector involved in Embodiment 20 is shown in the illustration. The peripheral structures of other through-holes 30 and other components of the plasma filter 3 are omitted.

[0251] like Figure 27 As shown, in a top view, the centers of multiple (e.g., two) slots 31 overlap each other. In a top view, the center of each slot 31 overlaps, for example, with the center of a through-hole 30. From a different viewpoint, in a top view, the fourth surface 3B of the plasma filter 3 has a so-called bullseye structure.

[0252] like Figure 28 As shown, the fourth surface 3B has multiple (e.g., 3) top surfaces 3F, multiple (e.g., 4) wall surfaces 3G, and multiple (e.g., 2) bottom surfaces 3H. Each groove 31 has two wall surfaces 3G and one bottom surface 3H. The two wall surfaces 3G of each groove 31 are radially opposed to each other relative to the bore axis of the through hole 30. The upper end of each wall surface 3G is connected to the inner or outer peripheral end of each top surface 3F. The lower end of each wall surface 31A is connected to the inner or outer peripheral end of each bottom surface 3H. Each wall surface 3G extends, for example, along the bore axis of the through hole 30. Each top surface 3F and each bottom surface 3H is, for example, orthogonal to the bore axis of the through hole 30. The inner peripheral end of the top surface 3F, located radially to the center of the through hole 30, is connected to the upper end of the inner peripheral surface 3C. An insulating layer 4 and a two-dimensional material layer 1 are disposed on multiple top surfaces 3F, multiple wall surfaces 3G, and multiple bottom surfaces 3H of the plasma filter 3. The first electrode portion 5 is disposed, for example, on the outermost top surface 3F located radially relative to the center of the through hole 30.

[0253] When viewed from above, each groove 31 surrounds only one through hole 30. When viewed from above, each groove 31 does not surround two adjacent through holes 30.

[0254] At least one of the through holes 30 has Figure 27 as well as Figure 28 The structure shown is acceptable, but for example, multiple through holes 30 each have Figure 27 as well as Figure 28 The structure shown.

[0255] In the electromagnetic wave detector according to Embodiment 20, when an electromagnetic wave is incident on the fourth surface 3B where the groove 31 is formed, a transmission-type surface plasmon resonance is generated in the plasma filter 3. The surface plasmon resonance is transmitted in the fourth surface 3B where the plurality of grooves 31 are formed and guided to the through hole 30, thus enhancing the intensity of the electromagnetic wave of the transmission plasma filter 3.

[0256] Furthermore, in the electromagnetic wave detector according to Embodiment 20, the detection wavelength is determined by the shape of the plurality of slots 31 (the period of the plurality of slots 31, the size of each slot 31, etc.), so compared with the electromagnetic wave detector 100 which does not have a plurality of slots 31, the setting of the detection wavelength has a higher degree of freedom.

[0257] At least one slot 31 can be formed in the plasma filter 3. The number of slots 31 can also be one. Alternatively, the number of slots 31 can be three or more. The spacing between two adjacent slots 31 in the radial direction is, for example, equal. This improves wavelength selectivity (monochromaticity). On the other hand, the spacing between adjacent slots 31 in the radial direction can also be different. This broadens the wavelength band of the electromagnetic waves emitted by the transmission plasma filter 3.

[0258] In cross-sectional view, each wall surface 3G can also have a conical shape. In other words, each wall surface 3G can also be inclined in such a way that the distance from the third surface 3A increases as it moves away from the center of the through hole 30.

[0259] The electromagnetic wave detector according to embodiment 20 may also have the same structure as any of the electromagnetic wave detectors according to embodiments 2 to 19, except that at least one groove 31 surrounding the through hole 30 is formed on the fourth surface 3B of the plasma filter 3.

[0260] Implementation method 21.

[0261] like Figure 29As shown, the electromagnetic wave detector array 300 according to Embodiment 21 is an assembly of multiple electromagnetic wave detectors 200. Each electromagnetic wave detector 200 is any one of the electromagnetic wave detectors 100 to 116 according to Embodiments 1 to 20.

[0262] exist Figure 29 In the electromagnetic wave detector array 300 shown, multiple electromagnetic wave detectors 200 are arranged periodically in a two-dimensional manner. Alternatively, multiple electromagnetic wave detectors 200 can be arranged periodically in a one-dimensional manner. Furthermore, the arrangement of the multiple electromagnetic wave detectors 200 can also be non-periodic, with different intervals.

[0263] exist Figure 29 In the electromagnetic wave detector array 300 shown, electromagnetic wave detectors 200 are arranged in a 2×2 matrix. However, the number of electromagnetic wave detectors 200 arranged is not limited to this. For example, multiple electromagnetic wave detectors 200 can be arranged in a matrix of 3 or more × 3.

[0264] Furthermore, in an electromagnetic wave detector array in which multiple electromagnetic wave detectors 200 are arranged in an array, the second electrode portion 6 can also be provided with a common electrode as long as the two-dimensional material layer 1 of each electromagnetic wave detector 200 is separated from each other. In an electromagnetic wave detector array in which the second electrode portion 6 is a common electrode, compared to an electromagnetic wave detector array in which the second electrode portions 6 of each electromagnetic wave detector 200 are independent, the wiring of pixels can be reduced and the resolution can be increased.

[0265] In addition, current cutting structures such as a semiconductor layer 2 trench structure can be formed to separate each electromagnetic wave detector 200 from each other.

[0266] The electromagnetic wave detector array 300 can also be used as an image sensor by arranging multiple electromagnetic wave detectors 200 in an array. The detection wavelengths of each electromagnetic wave detector 200 can be the same or different from each other.

[0267] Alternatively, the electromagnetic wave detector array 300 may also include a readout circuit configured to read out signals from each electromagnetic wave detector 200. Each electromagnetic wave detector 200 may also be configured on the readout circuit. The readout form of the readout circuit may be, for example, a CTAI (Capacitive Transimpedance Amplifier) ​​type. The readout circuit may also be of other readout forms.

[0268] Alternatively, the electromagnetic wave detector array 300 may also include bumps that electrically connect the first electrode portion 5 of each electromagnetic wave detector 200 to the readout circuit. The configuration where each electromagnetic wave detector 200 and the readout circuit are connected by bumps is called a hybrid junction. Hybrid junctions are a common configuration in quantum infrared sensors. In this case, each electromagnetic wave detector 200, for example, also has a pad electrically connected to the first electrode portion 5, and each bump is electrically connected to this pad. The material of the bumps is, for example, a conductive material such as indium (Ib). The material of the pads is a conductive material such as an aluminum-silicon (Al-Si) alloy, nickel (Ni), or gold (Au).

[0269] <Variation Example>

[0270] Figure 30 The electromagnetic wave detector array 301 shown has a structure that is substantially the same as that of the electromagnetic wave detector array 300, and achieves the same effect. However, it differs from the electromagnetic wave detector array 300 in that it comprises multiple electromagnetic wave detectors of different types, namely electromagnetic wave detectors 200, 201, 202, and 203. Each electromagnetic wave detector 200, 201, 202, and 203 is any one of the electromagnetic wave detectors 100 to 116 according to embodiments 1 to 20.

[0271] In the electromagnetic wave detector array 301, electromagnetic wave detectors 200, 201, 202, and 203 of different types are arranged in a matrix.

[0272] exist Figure 30 In this embodiment, electromagnetic wave detectors 200, 201, 202, and 203 are arranged in a 2×2 matrix, but the number of electromagnetic wave detectors is not limited to this. Furthermore, in this embodiment, different types of electromagnetic wave detectors 200, 201, 202, and 203 are arranged periodically in a two-dimensional manner, but they can also be arranged periodically in a one-dimensional manner. Alternatively, different types of electromagnetic wave detectors 200, 201, 202, and 203 can be arranged at different intervals without being periodic.

[0273] In the electromagnetic wave detector array 301, by arranging electromagnetic wave detectors 200, 201, 202, and 203 of different types involved in any of the embodiments 1 to 20 in a one-dimensional or two-dimensional array, it is possible to have the function of an image sensor. For example, electromagnetic wave detectors with different detection wavelengths can be used as electromagnetic wave detectors 200, 201, 202, and 203 respectively. Specifically, electromagnetic wave detectors with different detection wavelength selectivity can be prepared from the electromagnetic wave detectors involved in any of the embodiments 1 to 20 and arranged in an array. In this case, the electromagnetic wave detector assembly can detect electromagnetic waves of at least two different wavelengths.

[0274] By arranging electromagnetic wave detectors 200, 201, 202, and 203 with different detection wavelengths in such an array, similar to image sensors used in the visible light domain, it is possible to identify the wavelength of electromagnetic waves in any wavelength domain, such as the wavelength domains of ultraviolet light, infrared light, terahertz waves, and radio waves. As a result, for example, it is possible to obtain a colorized image that represents the difference in wavelength as a difference in color.

[0275] Furthermore, the semiconductor layer 2 of each of the electromagnetic wave detectors 200, 201, 202, and 203 can also be constructed using materials with different detection wavelengths. For example, semiconductor materials that detect wavelengths of visible light and those that detect wavelengths of infrared light can be used as the aforementioned constituent materials. In this case, for example, when the electromagnetic wave detector is applied to an automotive sensor, it can be used as a visible light imaging camera during the day. Furthermore, it can also be used as an infrared camera at night. Thus, it is not necessary to use separate cameras with image sensors based on the detection wavelength of the electromagnetic waves.

[0276] Furthermore, in applications other than image sensors, the electromagnetic wave detector can be used as a position detection sensor capable of detecting the position of objects even with a small number of pixels. For example, by constructing an assembly of electromagnetic wave detectors, if electromagnetic wave detectors 200, 201, 202, and 203 with different detection wavelengths are used as described above, an image sensor capable of detecting the intensity of electromagnetic waves of multiple wavelengths can be obtained. Thus, color images can be obtained by detecting electromagnetic waves of multiple wavelengths without the need for color filters, which are conventionally required in CMOS image sensors.

[0277] Furthermore, a polarization recognition image sensor can be formed by arraying electromagnetic wave detectors 200, 201, 202, and 203 that detect different polarizations. For example, polarization imaging can be performed by using four pixels with detected polarization angles of 0°, 90°, 45°, and 135° as a unit and configuring multiple electromagnetic wave detectors for each unit. With a polarization recognition image sensor, for example, it is possible to achieve the identification of man-made and natural objects, material identification, identification of objects at the same temperature in the infrared wavelength domain, identification of boundaries between objects, or equivalent resolution improvements.

[0278] Based on the above, the electromagnetic wave detector assembly of this embodiment, configured as described above, can detect electromagnetic waves over a wide wavelength range. Furthermore, the electromagnetic wave detector assembly of this embodiment can detect electromagnetic waves of different wavelengths.

[0279] The embodiments disclosed herein should be considered illustrative and not restrictive in all respects. At least two embodiments of this disclosure may be combined, provided there is no contradiction. The scope of this disclosure is set forth in the claims, not the foregoing description, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. An electromagnetic wave detector, comprising: At least one photoelectric conversion element; and A plasma filter is configured to be opposite to the at least one photoelectric conversion element. The plasma filter has multiple through holes formed periodically. The at least one photoelectric conversion element comprises: A semiconductor layer having a region that overlaps with at least one of the plurality of through holes when viewed from above; An insulating layer is formed to cover a portion of the area; A two-dimensional material layer is disposed on another portion of the region and on the insulating layer and is electrically connected to the other portion of the region; The first electrode portion is electrically connected to the two-dimensional material layer; as well as The second electrode portion is electrically connected to the semiconductor layer. The two-dimensional material layer comprises any material selected from the group consisting of transition metal dichalcogenides, graphene, black phosphorus, silicene, germanene, graphene nanoribbons, and borophene.

2. The electromagnetic wave detector according to claim 1, wherein, In the at least one photoelectric conversion element, The semiconductor layer has multiple regions that overlap with two or more of the plurality of through holes when viewed from above. The two-dimensional material layer is electrically connected to the other portions of each of the plurality of regions.

3. The electromagnetic wave detector according to claim 1 or 2, wherein, The plasma filter is disposed on the same side as the insulating layer, the two-dimensional material layer, and the first electrode portion, relative to the semiconductor layer. The insulating layer extends from a portion of the region to a portion of the plasma filter. The two-dimensional material layer extends from the other portion of the region onto the insulating layer disposed on the plasma filter. The first electrode portion is disposed on the insulating layer disposed on the plasma filter.

4. The electromagnetic wave detector according to claim 1 or 2, wherein, The plasma filter is disposed on the side opposite to the semiconductor layer, which is opposite to the insulating layer, the two-dimensional material layer, and the first electrode portion.

5. The electromagnetic wave detector according to claim 1 or 2, wherein, The material constituting at least a portion of the surface of the plasma filter is a material that generates surface plasmon resonance when electromagnetic waves are incident.

6. The electromagnetic wave detector according to claim 5, wherein, The plasma filter includes a core material and a coating material disposed on at least a portion of the surface of the core material. The material constituting the coating is a material that generates surface plasmon resonance when electromagnetic waves are incident.

7. The electromagnetic wave detector according to claim 5, wherein, The plasma filter includes a first component and a second component stacked along the respective aperture axis directions of the plurality of through holes. The material constituting the first component is a material that generates surface plasmon resonance when electromagnetic waves are incident on it. The material constituting the second component is a dielectric.

8. The electromagnetic wave detector according to claim 1 or 2, wherein, In the plasma filter, the wavelength band of surface plasma being excited is narrower than the wavelength band of sensitivity of the semiconductor layer.

9. The electromagnetic wave detector according to claim 1 or 2, wherein, The plurality of through holes are arranged periodically along at least one direction.

10. The electromagnetic wave detector according to claim 9, wherein, The semiconductor layer is sensitive to the detection wavelength. The period of the plurality of through holes is equal to the detection wavelength.

11. The electromagnetic wave detector according to claim 1 or 2, wherein, The inner circumferential surfaces of the plurality of through holes are inclined relative to the hole axes of the plurality of through holes.

12. The electromagnetic wave detector according to claim 1 or 2, wherein, The cross-sectional shape of the inner circumferential surface of each of the plurality of through holes is stepped.

13. The electromagnetic wave detector according to claim 1 or 2, wherein, When viewed from above, at least one groove is formed on the surface of the plasma filter, surrounding one of the plurality of through holes.

14. The electromagnetic wave detector according to claim 1 or 2, wherein, The ends of the two-dimensional material layer are disposed on the region.

15. The electromagnetic wave detector according to claim 1 or 2, wherein, It also includes a buffer layer disposed between the region of the semiconductor layer and the two-dimensional material layer.

16. The electromagnetic wave detector according to claim 15, wherein, The buffer layer has a thickness capable of forming a tunneling current between the two-dimensional material layer and the semiconductor layer.

17. The electromagnetic wave detector according to claim 1 or 2, wherein, It also includes a connecting conductor that electrically connects the region of the semiconductor layer and the two-dimensional material layer.

18. The electromagnetic wave detector according to claim 1 or 2, wherein, The semiconductor layer includes: The first semiconductor portion has a first conductivity type; and The second semiconductor portion, bonded to the first semiconductor portion, has a second conductivity type. The bonding interface between the first semiconductor portion and the second semiconductor portion is disposed within the region.

19. The electromagnetic wave detector according to claim 18, wherein, The absorption wavelength of the first semiconductor portion is different from that of the second semiconductor portion.

20. The electromagnetic wave detector according to claim 1 or 2, wherein, When viewed from above, the first electrode portion is formed in a ring shape, and the region is located further inward than the first electrode portion.

21. The electromagnetic wave detector according to claim 1 or 2, wherein, The thickness of the insulating layer varies as one approaches the first electrode portion from the region.

22. The electromagnetic wave detector according to claim 1 or 2, wherein, A void is formed between the semiconductor layer and the two-dimensional material layer.

23. The electromagnetic wave detector according to claim 1 or 2, wherein, It also has a contact layer configured to contact the two-dimensional material layer.

24. The electromagnetic wave detector according to claim 1 or 2, wherein, The two-dimensional material layer includes a disordered layer structure. The disordered layer structure portion is at least disposed on the insulating layer.

25. An electromagnetic wave detector array, wherein, Possessing an electromagnetic wave detector according to any one of claims 1 to 24, The plurality of electromagnetic wave detectors are arranged along at least one of the first direction and the second direction.

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