Electrical modulation two-color detector based on semiconductor nanowire array, manufacturing method and application

Abstract

The invention discloses an electrical modulation two-color detector based on a semiconductor nanowire array, a manufacturing method and application, a layer of heavily doped n-type GaAs buffer layer is epitaxially grown on a GaAs substrate, a layer of gold film is deposited on the surface of the buffer layer and annealing treatment is carried out, and then a vertical GaAs nanowire array is grown on a sample. And filling the periphery of the vertically arranged nanowire array with a BCB polymer for curing and supporting, and depositing a Ga-doped ZnO film on the upper surfaces of the nanowire array and the BCB polymer. According to the distinguishing method of the electric modulation double-color detector, under positive and negative bias voltages, the working mode of the detector is converted between a visible detection mode and an infrared detection mode. The method comprises the following steps: respectively measuring a first responsivity R1 of a detector under a first polarity bias voltage and a second responsivity R2 of the detector under a second polarity bias voltage; calculating a responsivity ratio R1 / R2; and comparing the responsivity ratio with a pre-stored calibration database so as to determine the wavelength of the incident monochromatic light.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of photoelectric detectors, in particular to an electric modulation dual-color detector based on a semiconductor nanowire array, a manufacturing method and application. BACKGROUND

[0002] Dual-color detection is a solid-state sensing technology integrating dual-band spectral detection capability, which can significantly improve the detection efficiency of photoelectric systems and is suitable for identification and tracking of multiple target groups (human bodies, animals, fixed obstacles, rapidly moving objects, etc.) in complex environments and has wide application in the fields of security and protection, industrial monitoring, automatic driving of vehicles, remote sensing guidance, etc.

[0003] Through the analysis of the prior art, it is not difficult to find that the existing three-terminal and two-terminal structures can realize the functional requirements of dual-color detection, such as the dual-color infrared detector and its manufacturing method with the authorization announcement number CN111799350B and the dual-color infrared detector and its manufacturing method with the authorization announcement number CN112786731B, but the complex structure is easy to bring limitations in waveband selection, scale expansion of the area array, cost, yield, etc. Specifically, first, the energy band engineering dilemma; the existing dual-color devices generally adopt the technical route of "energy band engineering to tailor the spectrum", and the device therefore contains materials with different band gaps and doping conditions. This makes researchers not only need to accurately calculate the energy band arrangement, but also need to evaluate the lattice mismatch degree and the performance degradation caused thereby. Especially for the latter, it is difficult for people to find a perfect solution under the existing framework, which to a large extent limits the waveband expansion and performance output of the dual-color device. Second, the process complexity trap; as mentioned above, the device contains materials with different band gaps and doping conditions, which must assume their respective roles according to the set thickness, composition, energy gap, conductivity, spatial layout, etc. in order to finally realize the dual-color function. This puts very high requirements on material growth and device process, such as precise control of material composition / doping / thickness, complex and precise photolithography, etching, ion implantation, surface passivation process, etc., which ultimately leads to high device cost, low yield and limited scale of the area array. SUMMARY

[0004] The application aims to provide an electric modulation dual-color detector based on a semiconductor nanowire array, a manufacturing method and application, which breaks through the limitations of the existing technology in waveband selection, scale expansion of the area array, cost, yield, etc.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the application is:

[0006] The application discloses a semiconductor nanowire array-based electrically modulated dual-color detector, characterized in that the detector has a GaAs substrate, an n-doped GaAs buffer layer and a GaAs nanowire array are sequentially grown on the GaAs substrate from bottom to top, and a transparent top electrode is arranged on the top of the GaAs nanowire array; the GaAs nanowire array is filled with a dielectric filler; a semiconductor thin film is further arranged between the root of the GaAs nanowire array and the GaAs buffer layer; and the GaAs buffer layer is further provided with a base electrode; the dual-color detector is in a visible light detection mode under positive bias and in an infrared light detection mode under negative bias.

[0007] The diameter of the nanowire in the GaAs nanowire array is about 95 nm, the length is about 4 um, and the spacing between adjacent nanowires is about 280 nm.

[0008] The dielectric filler is a benzocyclobutene polymer or polymethyl methacrylate.

[0009] The transparent top electrode is a transparent conductive oxide thin film, which is Ga-doped ZnO, the sheet resistance is about 50 Ω / □, and the average light transmittance in the visible light and near-infrared waveband is greater than 80%; the base electrode is a gold thin film with a thickness of 200 nm.

[0010] The semiconductor thin film is a GaAs thin film rich in lattice defects.

[0011] The positive bias is +5 V, and the negative bias is -5 V.

[0012] The application further discloses a manufacturing method of the electrically modulated dual-color detector.

[0013] S1, depositing an n-doped GaAs buffer layer on a GaAs substrate;

[0014] S2, depositing a gold film with a thickness of 10 nm on the GaAs buffer layer by thermal evaporation, and then annealing at 550 DEG C for five minutes to generate randomly distributed liquid drop state gold on the GaAs buffer layer;

[0015] S3, transferring the sample after S2 into a molecular beam epitaxy device to grow a vertical GaAs nanowire array at 480 DEG C; during the growth of the GaAs nanowire array, a semiconductor thin film is formed at the root of the GaAs nanowire array, and the semiconductor thin film is a GaAs thin film rich in lattice defects;

[0016] S4, filling the GaAs nanowire array with a dielectric filler and solidifying; the dielectric filler is a benzocyclobutene polymer or polymethyl methacrylate;

[0017] S5, a transparent top electrode is formed by depositing a Ga-doped ZnO thin film on the top surface of the GaAs nanowire array; a 200 nm thick gold thin film is deposited on the GaAs buffer layer as the base electrode.

[0018] In S3, the growth process lasted for 2 hours, and the V / III flux ratio was set to 20:1.

[0019] An application of the electrically modulated dual-color detector as described above in measuring the wavelength of monochromatic light involves measuring the first responsivity R1 under a first polarity bias and the second responsivity R2 under a second polarity bias under a fixed optical power illumination; calculating the responsivity ratio R1 / R2; and comparing the responsivity ratio with a pre-stored calibration database to determine the wavelength of the incident monochromatic light.

[0020] The responsivity ratios under visible light detection mode and infrared light detection mode are measured respectively. The responsivity ratios under the two detection modes are compared with a pre-stored calibration database to determine the wavelength of the incident monochromatic light.

[0021] In view of the above technical features, the present invention has the following beneficial effects: 1. Compared with ordinary nanowire arrays, the nanowire array of this patent breaks through the mutual limitation between high-efficiency absorption and high gain, realizes electrically modulated dual-color band responsivity, and has built-in recognition capability. It eliminates the need for discrete optical components, allowing a single device to directly distinguish the wavelengths of different monochromatic lights. This provides a completely new device solution for future intelligent sensing, on-chip spectral analysis, and advanced optical communication systems. 2. Utilizing a unique vertical nanowire array structure, the sensitivity of the detector to visible or infrared light can be actively adjusted simply by changing the polarity of the applied bias voltage, thereby even distinguishing monochromatic lights of different wavelengths. This solution eliminates the need for complex bandgap design, heteroepitaxial growth, and fabrication processes, significantly lowering the development threshold for dual-color devices. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the dual-color photodetector of the present invention;

[0023] Figure 2 This is a SEM image of the side of a GaAs nanowire array;

[0024] Figure 3 This is a visible / infrared response diagram enhanced by positive / negative bias voltage;

[0025] Figure 4 This refers to the ratio R of the light response at +5V and -5V for 520nm, 637nm, and 830nm light. +5V / R -5V；

[0026] Figure 5 This is a schematic diagram of the photocarrier transport process of vertically aligned GaAs nanowires under +5 V and -5 V bias.

[0027] In the figure: 1-GaAs substrate; 2-GaAs buffer layer; 3-semiconductor thin film; 4-GaAs nanowire array; 5-dielectric filler; 6-transparent top electrode; 7-base electrode. Detailed Implementation

[0028] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that these drawings and embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that some components well-known to those skilled in the art but not related to the main content of the present invention may be omitted in the drawings or description. Additionally, for ease of description, some components in the drawings may be omitted, enlarged, or reduced, but this does not represent the actual size or complete structure of the product.

[0029] An electrically modulated dual-color detector based on a semiconductor nanowire array, such as Figure 1 As shown, it has a GaAs substrate 1, on which an n-type doped GaAs buffer layer 2 and a GaAs nanowire array 4 are grown sequentially from bottom to top. A transparent top electrode 6 is disposed on the top of the GaAs nanowire array 4. The GaAs nanowire array 4 is filled with a dielectric filler 5. A semiconductor thin film 3 is also disposed between the root of the GaAs nanowire array 4 and the GaAs buffer layer 2. A base electrode 7 is also disposed on the GaAs buffer layer 2.

[0030] Preferably, the nanowires in the GaAs nanowire array 4 are vertically aligned, with a diameter of approximately 95 nm, a length of approximately 4 μm, and a spacing of approximately 280 nm between adjacent nanowires. This specific nanowire array structure ensures excellent optical response of the device.

[0031] The semiconductor thin film 3 is a GaAs thin film rich in lattice defects, which is formed at the root of the GaAs nanowire array 4 along with the growth of the GaAs nanowire array 4.

[0032] The dielectric filler 5 is a benzocyclobutene polymer or a BCB polymer of polymethyl methacrylate. The BCB polymer is used to fill and support the vertically aligned nanowire array.

[0033] In this structure, the vertical GaAs nanowires serve as the light absorption layer and carrier transport channels, while the BCB polymer not only provides mechanical support but also acts as electrical insulation to prevent lateral leakage current.

[0034] The transparent top electrode 6 is a transparent conductive oxide thin film, which is Ga-doped ZnO with a sheet resistance of about 50 Ω / □ and an average transmittance of more than 80% in the visible and near-infrared bands; the base electrode 7 is a gold thin film with a thickness of 200 nm.

[0035] The transparent top electrode 6 ensures both good light transmittance and uniform surface contact, which is beneficial for efficient carrier collection. The base electrode 7 of the bottom gold thin film forms an ohmic contact with the n-type doped GaAs buffer layer 2, significantly reducing contact resistance and improving the overall electrical performance of the device. The overall structural coordination is a prerequisite for realizing the dual-color detector function.

[0036] The final structure consists of a "sandwich" device: GaAs substrate 1 | n-GaAs buffer layer 2 (a thin gold film is deposited on the substrate) | defect-rich GaAs film | vertical GaAs nanowire array 4 (embedded in BCB) | top GZO transparent top electrode 6.

[0037] This dual-color detector operates in visible light detection mode under positive bias and in infrared light detection mode under negative bias. Preferably, the positive bias is +5V and the negative bias is -5V.

[0038] The implementation of the electrically modulated dual-color detection mechanism, such as Figure 3 As shown, this response is highly dependent on the polarity of the bias voltage and the wavelength of the incident light. Following the pattern in the image, positive / negative bias voltages enhance the visible / infrared light response. This is because by changing the polarity of the bias voltage, the direction of motion of photogenerated carriers can be actively controlled, causing them to interact "cooperatively" or "non-cooperatively" with the wavelength-dependent light field distribution, thereby selectively enhancing the response to different wavelength bands. Figure 5 As shown, for short wavelengths such as 520nm green light, the light field is localized at the top of the nanowire. Under a +5V bias, reverse hole injection effectively suppresses the overall depletion layer, producing a highly responsible "visible light enhancement" mode. However, under a -5V bias, holes are rapidly extracted from the top, resulting in limited gain and low responsivity. For long wavelengths such as 830nm infrared light, the light field is localized at the bottom of the nanowire. Under a -5V bias, holes are collected at the bottom, activating the photoconductor gain and producing a high-responsivity "infrared enhancement" mode. However, under a +5V bias, holes have a long path to the bottom and are prone to recombination, resulting in low responsivity. Meanwhile, as... Figure 4 As shown, the ratio R of the light response at +5V and -5V for 520nm, 637nm, and 830nm light is... +5V / R -5V The values ​​taken are averages under different light intensities, and R is the average value under different wavelengths. +5V / R -5VThe values ​​exhibit a certain pattern: approximately 6 (greater than 6) at 520nm, approximately 3 at 637nm, and approximately 0.8 at 830nm. Comparing these responsivity ratios with a pre-stored calibration database allows the detector to acquire a certain monochromatic light recognition function.

[0039] An application based on the aforementioned electrically modulated dual-color detector is used to determine the wavelength of monochromatic light. Specifically, under monochromatic light illumination with a fixed optical power, the first responsivity R1 of the electrically modulated dual-color detector under a first polarity bias voltage and the second responsivity R2 under a second polarity bias voltage are measured respectively; the responsivity ratio R1 / R2 is calculated; and the responsivity ratio is compared with a pre-stored calibration database to determine the wavelength of the incident monochromatic light.

[0040] The responsivity ratios under visible light detection mode and infrared light detection mode are measured respectively. The responsivity ratios under the two detection modes are compared with a pre-stored calibration database to determine the wavelength of the incident monochromatic light.

[0041] The fabrication method for the electrically modulated dual-color detector described above involves the following steps:

[0042] S1, deposit an n-type doped GaAs buffer layer 2 on GaAs substrate 1;

[0043] S2, a 10 nm thick gold film is deposited on GaAs buffer layer 2 by thermal evaporation, and then annealed at 550 °C for five minutes. The gold film generates randomly distributed droplet-like gold particles on GaAs buffer layer 2. These droplet-like gold particles are nanocatalyst droplets, which are the "seeds" and "templates" that initiate and guide the solid-liquid-gas growth of the entire GaAs nanowire array.

[0044] The principle is that after annealing, the continuous gold film breaks down and aggregates into nanoscale liquid gold particles (droplets). In the subsequent MBE growth environment, gaseous gallium (Ga) and arsenic (As) components are absorbed and dissolved by these liquid gold particles, forming gold-gallium-arsenic alloy droplets. When the Ga and As in the alloy droplets reach a supersaturated state, they crystallize out from the interface between the droplet and the substrate, forming solid GaAs crystals. As reactants are continuously supplied from the gas phase to the droplets and continuously precipitate, the crystal grows one-dimensionally upwards, eventually "topping" the gold droplet above, forming a nanowire.

[0045] S3, the sample completed in S2 is transferred to a molecular beam epitaxy (MBE) device and grown at 480°C to form a shape like... Figure 2 The vertical GaAs nanowire array 4 is shown; the growth process took 2 hours and the V / III flux ratio was set to 20:1.

[0046] During the growth of the GaAs nanowire array 4, a semiconductor thin film 3 is formed at the root of the GaAs nanowire array 4. This semiconductor thin film 3 is a GaAs thin film rich in lattice defects. This thin film contains abundant lattice defects, and defect energy levels exist within its bandgap, which are used to extend the spectral response range of the detector beyond the intrinsic absorption cutoff wavelength of the semiconductor nanowire.

[0047] During the self-organized growth of GaAs nanowire array 4, Ga and As atoms are randomly deposited on the substrate surface, forming a rich thin film layer. Typically, low-temperature growth processes (480℃) are favorable for forming defect-rich GaAs films, which mainly originate from lattice mismatch and atomic disorder under non-ideal growth conditions.

[0048] S4, fill the GaAs nanowire array 4 with dielectric filler 5 and cure it; dielectric filler 5 is benzocyclobutene polymer or polymethyl methacrylate.

[0049] S5, a transparent top electrode 6 is formed by depositing a Ga-doped ZnO thin film on the top surface of the GaAs nanowire array 4; a gold thin film with a thickness of 200 nm is deposited on the GaAs buffer layer 2 as a base electrode 7.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. All equivalent changes and modifications made within the scope of the claims of this invention should be considered within the technical scope of this invention.

Claims

1. An electrically modulated dual-color detector based on a semiconductor nanowire array, characterized in that: It has a GaAs substrate (1), on which an n-type doped GaAs buffer layer (2) and a GaAs nanowire array (4) are grown sequentially from bottom to top. A transparent top electrode (6) is provided on the top of the GaAs nanowire array (4). The GaAs nanowire array (4) is filled with a dielectric filler (5). A semiconductor thin film (3) is also provided between the root of the GaAs nanowire array (4) and the GaAs buffer layer (2). A base electrode (7) is also provided on the GaAs buffer layer (2). The dual-color detector is in visible light detection mode under positive bias and in infrared light detection mode under negative bias.

2. The electrically modulated dual-color detector as described in claim 1, characterized in that: The diameter of the nanowires in the GaAs nanowire array (4) is about 95 nm, the length is about 4 μm, and the spacing between adjacent nanowires is about 280 nm.

3. The electrically modulated dual-color detector as described in claim 1, characterized in that: The dielectric filler (5) is a benzocyclobutene polymer or polymethyl methacrylate.

4. The electrically modulated dual-color detector as described in claim 1, characterized in that: The transparent top electrode (6) is a transparent conductive oxide film, which is Ga-doped ZnO with a sheet resistance of about 50 Ω / □ and an average transmittance of more than 80% in the visible and near-infrared bands; the base electrode (7) is a gold film with a thickness of 200 nm.

5. The electrically modulated dual-color detector as described in claim 1, characterized in that: The semiconductor thin film (3) is a GaAs thin film rich in lattice defects.

6. The electrically modulated dual-color detector as described in claim 1, characterized in that: The positive bias voltage is +5V, and the negative bias voltage is -5V.

7. The method for manufacturing an electrically modulated dual-color detector as described in any one of claims 1-6, characterized in that: The production steps are as follows: S1, deposit an n-type doped GaAs buffer layer (2) on the GaAs substrate (1). S2, a gold film with a thickness of 10 nm is deposited on the GaAs buffer layer (2) by thermal evaporation, and then annealed at 550 °C for five minutes to generate randomly distributed droplet gold on the GaAs buffer layer (2). S3, the sample completed in S2 is transferred to a molecular beam epitaxy device and grown at 480°C to form a vertical GaAs nanowire array (4); during the growth of the GaAs nanowire array (4), a semiconductor thin film (3) is formed at the root of the GaAs nanowire array (4), which is a GaAs thin film rich in lattice defects. S4, fill the GaAs nanowire array (4) with dielectric filler (5) and cure it; the dielectric filler (5) is a benzocyclobutene polymer or polymethyl methacrylate; S5, deposit a transparent top electrode (6) with a Ga-doped ZnO thin film on the top surface of the GaAs nanowire array (4); deposit a gold thin film with a thickness of 200 nm on the GaAs buffer layer (2) as the base electrode (7).

8. The method for manufacturing an electrically modulated dual-color detector as described in claim 7, characterized in that: In S3, the growth process lasted for 2 hours, and the V / III flux ratio was set to 20:

1.

9. An application of the electrically modulated dual-color detector according to any one of claims 1-6 in measuring the wavelength of monochromatic light, characterized in that: Under monochromatic light illumination at a fixed optical power, the first responsivity R1 under the first polarity bias and the second responsivity R2 under the second polarity bias of the electrically modulated dual-color detector are measured respectively; the responsivity ratio R1 / R2 is calculated; and the responsivity ratio is compared with a pre-stored calibration database to determine the wavelength of the incident monochromatic light.

10. The application as described in claim 9, characterized in that: The responsivity ratios under visible light detection mode and infrared light detection mode are measured respectively. The responsivity ratios under the two detection modes are compared with a pre-stored calibration database to determine the wavelength of the incident monochromatic light.

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