Phototransistor structure, photodetection array structure and photodetection method

Abstract

This invention provides a phototransistor structure, a photodetector array structure, and a photodetector method. The phototransistor structure includes a thin-film transistor (TFT), which comprises a substrate layer and a channel layer, a source / drain electrode layer, a gate dielectric layer, and a transparent gate electrode layer sequentially formed thereon. A Schottky photodiode exhibiting localized surface plasmon resonance (SPR) is disposed between the gate dielectric layer and the transparent gate electrode layer of the TFT. By disposing a Schottky photodiode with SPR between the gate dielectric layer and the transparent gate electrode layer of the TFT, the hot carriers generated by the photodiode under the SPR can be used to change the potential distribution and gate voltage in the channel layer of the TFT, thereby achieving exponential amplification of the weak hot carrier signal generated by the SPR, effectively improving the sensitivity and signal-to-noise ratio of the plasmonic photodetector.

Description

Technical Field

[0001] This invention relates to the field of photoelectric detection technology, and in particular to a phototransistor structure, a photoelectric detection array structure, and a photoelectric detection method. Background Technology

[0002] Surface plasmon photonics is a very important part of the field of nano-optics. Surface plasmons are electromagnetic oscillations generated by the interaction of incident photons with free electrons on the surface of a material. They can localize electromagnetic field energy in a region much smaller than the wavelength, thereby significantly enhancing the interaction between light and matter.

[0003] Photodetection based on hot carriers (hot electrons or hot holes) generated by surface plasmon decay is an important technological approach in recent years to overcome the bandgap limitation of semiconductors and achieve wide-spectrum (especially infrared) detection. Traditional plasmon hot carrier detectors typically employ a metal-semiconductor (Schottky) diode structure. Their working principle is based on the internal photoemission (IPE) effect: high-energy hot carriers generated by the non-radiative decay of plasmons, if their energy is higher than the Schottky barrier height at the metal-semiconductor interface, can overcome the barrier and be injected into the semiconductor for collection, forming a photocurrent.

[0004] However, existing plasmonic photodetectors based on Schottky diode structures face significant challenges in practical applications, mainly in the following aspects: 1. Low photoelectric conversion efficiency: The generation, transmission and emission of hot carriers have large losses, and in reality, the number of carriers that can successfully cross the potential barrier and be collected is small, resulting in a low quantum efficiency (EQE) of the device (often less than 1%).

[0005] 2. Poor signal-to-noise ratio: Since the collected photocurrent signal is relatively weak, it often requires a high-precision external amplifier circuit for reading. This not only increases the complexity of the system, but also easily introduces additional circuit noise, limiting the device's ability to detect weak light signals.

[0006] 3. Lack of internal gain mechanism: Traditional diode structures are merely passive collectors of charge carriers and cannot amplify signals in situ.

[0007] Therefore, how to retain the advantage of plasmonic detectors in breaking the bandgap limitation while effectively amplifying weak hot carrier signals to improve the sensitivity and signal-to-noise ratio of plasmonic detectors has become a technical problem that the industry urgently needs to solve. Summary of the Invention

[0008] In view of the above problems, the present invention provides a phototransistor structure, a photodetector array structure, and a photodetector method, which can effectively amplify weak hot carrier signals to improve the sensitivity and signal-to-noise ratio of plasmonic detectors, and is easy to integrate on a large scale to achieve high-density, low-power, and fast-response photodetection.

[0009] According to a first aspect of the present invention, a phototransistor structure is provided, comprising: Thin-film transistor, the thin-film transistor comprising a substrate layer and a channel layer, a source / drain electrode layer, a gate dielectric layer, and a transparent gate electrode layer sequentially formed on the substrate layer; and A photodiode is disposed between the gate dielectric layer and the transparent gate electrode layer; the photodiode exhibits localized surface plasmon resonance (FSPR) effect; wherein, the photodiode comprises: A receiving layer is formed on the gate dielectric layer and is in contact with the gate dielectric layer; The excitation layer comprises N metasurface unit structures, which are arrayed on the receiving layer, and each metasurface unit structure forms a Schottky contact with the receiving layer; where N is a positive integer. A first insulating layer is formed on the receiving layer and fills the spaces between adjacent metasurface unit structures, separating each metasurface unit structure. The transparent gate electrode layer covers the N metasurface unit structures and the first insulating layer.

[0010] Optionally, the material of the metasurface unit structure is a single material or a composite material; The single material is a metallic material, a metallic compound material, or a two-dimensional material; the composite material includes a combination of at least two of the following: metallic materials, metallic compound materials, and two-dimensional materials.

[0011] Optionally, the metasurface unit structure has a planar geometric shape or a periodic array pattern parallel to the cross-section of the channel layer.

[0012] Optionally, the photodiode further includes a reflective layer formed between the receiving layer and the gate dielectric layer.

[0013] Optionally, the reflective layer is a metallic reflective layer or a Bragg reflective stack.

[0014] Optionally, the material of the receiving layer is at least one or a combination of elemental semiconductor materials, oxide semiconductor materials, compound semiconductor materials, two-dimensional materials, and organic semiconductor materials.

[0015] Optionally, the material of the first insulating layer is at least one or a combination of SiO2, Si3N4, Al2O3, HfO2, ZrO2, Ta2O5, and Y2O3.

[0016] Optionally, a second insulating layer is further included between the substrate layer and the channel layer; the material of the second insulating layer is at least one or a combination of SiO2, Si3N4, Al2O3, HfO2, ZrO2, Ta2O5, and Y2O3.

[0017] According to a second aspect of the present invention, a photodetector array structure is also provided, the photodetector array structure comprising M phototransistor structures as described in the first aspect above, wherein M≥2, all phototransistor structures are connected along the X direction, Y direction or X / Y direction of a two-dimensional plane to form an array of m rows and n columns of phototransistor structures, wherein m and n are positive integers; the source of the phototransistor structure in each row is connected in series with the drain of the adjacent phototransistor structure to form a row of bit signal lines; the gates of all phototransistor structures in each column are connected in series to form a column of word signal lines.

[0018] According to a third aspect of the present invention, a photoelectric detection method is also provided, which uses a photoelectric detection array structure as described in the second aspect above for photoelectric detection, comprising: Under background light illumination, a first voltage is applied to all word signal lines in the photodetector array structure to turn on and keep all phototransistor structures in the photodetector array structure in the on state. A second voltage is applied to all bit signal lines in the photodetector array structure to generate source-drain current in each row bit signal line; A third voltage is applied to the word signal line corresponding to the phototransistor structure to be selected in the photodetector array structure, so that the phototransistor structure to be selected is in the subthreshold operating region, and the source-drain current value in the bit signal line corresponding to the phototransistor structure to be selected is read as the first current value. Under the illumination of the probe light, the source and drain current values ​​in the corresponding bit signal lines of the phototransistor structure to be selected are read as the second current value. The difference between the first current value and the second current value is calculated to obtain the photodetector signal of the desired selected phototransistor structure.

[0019] The phototransistor structure provided by this invention includes a thin-film transistor (TFT), which comprises a substrate layer and a channel layer, a source / drain electrode layer, a gate dielectric layer, and a transparent gate electrode layer sequentially formed thereon. A Schottky photodiode exhibiting localized surface plasmon resonance (SPR) is further disposed between the gate dielectric layer and the transparent gate electrode layer of the TFT. By disposing a Schottky photodiode with SPR between the gate dielectric layer and the transparent gate electrode layer of the TFT, the hot carriers generated by the Schottky photodiode under the SPR can be used to change the potential distribution in the channel layer of the TFT, thereby controlling the gate voltage of the TFT. This allows for the in-situ conversion of the optical signal into the gate voltage signal of the TFT, achieving exponential amplification of the weak hot carrier signal generated by the SPR, and effectively improving the sensitivity and signal-to-noise ratio of the plasmonic photodetector. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a top view schematic diagram of a phototransistor structure provided in an embodiment of the present invention; Figure 2 It corresponds Figure 1 A schematic diagram of the cross-sectional structure of a phototransistor at section A-A'; Figure 3 This is an example group of cross-sectional patterns of the metasurface unit structure array of the excitation layer of the phototransistor structure provided in the embodiments of the present invention, which are parallel to the channel layer. Figure 4 This is a schematic diagram of a phototransistor structure including a reflective layer provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of a phototransistor structure including a second insulating layer provided in an embodiment of the present invention; Figure 6 This is an equivalent circuit diagram of a photoelectric detection array structure provided in an embodiment of the present invention; Figure 7 This is a top view schematic diagram of the photoelectric detection array structure provided in an embodiment of the present invention; Figure 8 This is a schematic flowchart of a photoelectric detection method provided in an embodiment of the present invention.

[0022] Explanation of reference numerals in the attached figures: 101 - Substrate layer; 102 - Channel layer; 103 - Gate dielectric layer; 1041 - Source electrode layer; 1042 - Drain electrode layer; 105 - Transparent gate electrode layer; 106 - Second insulating layer; 20 - Photodiode; 201 - Receiver Layer; 202 - Excitation layer; 203 - First insulating layer; 204 - Reflective layer. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0025] As described in the background section, existing plasmonic photodetectors based on Schottky diode structures face significant challenges in practical applications, including low photoelectric conversion efficiency, poor signal-to-noise ratio, and lack of internal gain mechanisms.

[0026] In view of this, the present invention provides a phototransistor structure, including a thin-film transistor (TFT). The TFT includes a substrate layer and a channel layer, a source / drain electrode layer, a gate dielectric layer, and a transparent gate electrode layer sequentially formed thereon. A Schottky photodiode exhibiting localized surface plasmon resonance (SPR) is further disposed between the gate dielectric layer and the transparent gate electrode layer of the TFT. By disposing a Schottky photodiode with SPR between the gate dielectric layer and the transparent gate electrode layer of the TFT, the hot carriers generated by the Schottky photodiode under the SPR can be used to change the potential distribution in the channel layer of the TFT, thereby controlling the gate voltage of the TFT. This allows for the in-situ conversion of the optical signal into the gate voltage signal of the TFT, achieving exponential amplification of the weak hot carrier signal generated by the SPR, and effectively improving the sensitivity and signal-to-noise ratio of the plasmonic photodetector.

[0027] Please refer to Figure 1 , Figure 2 The phototransistor structure provided in one embodiment of the present invention includes: A thin-film transistor includes a substrate layer 101 and a channel layer 102, a source electrode layer 1041, a drain electrode layer 1042, a gate dielectric layer 103, and a transparent gate electrode layer 105 sequentially formed on the substrate layer 101.

[0028] In one specific implementation, the substrate 101 can be made of, for example, single-crystal silicon or single-crystal germanium. In a preferred embodiment, the substrate 101 can be made of, for example, intrinsic silicon or germanium, or high-resistivity silicon or germanium, to effectively reduce the parasitic leakage current of the substrate and improve the detection sensitivity of the phototransistor structure. Of course, this invention is not limited to these methods; other types of substrate materials, such as silicon carbide and gallium nitride, are also within the scope of this invention.

[0029] As an example, the material of the channel layer 102 can be, for example, an elemental semiconductor material, such as single-crystal, polycrystalline, or amorphous Si or Ge; an alloy semiconductor material, such as SiGe, AlGaAs, AlInAs, GaAsP, GaInP, GaInAs, and GaInAsP; a compound semiconductor material, such as SiC, GaN, GaAs, GaP, InP, and InAs; or a two-dimensional semiconductor, such as MoS2 or graphene. Of course, this invention is not limited to these types of materials; other types of channel layer 102 materials, such as oxide semiconductor materials, organic semiconductor materials, or combinations thereof, are also within the scope of protection of this invention.

[0030] As an example, the material of the gate dielectric layer 103 may be an oxide or nitride composed of at least one of the elements Si, Al, Hf, Zr, Ba, Ti, Ta, and Y. Of course, this invention is not limited thereto, and other types of oxide or nitride gate dielectric layer materials are also within the scope of protection of this invention.

[0031] As a specific implementation, the source electrode layer 1041 and the drain electrode layer 1042 can be made of a single metal material, such as Mg, Al, Ti, Mn, Ni, Cu, Zn, Ga, Zr, Nb, Mo, Pd, Ag, In, Sn, Ta, W, Pt, Au, Co, etc.; or binary or multi-element alloy materials, oxides and nitrides of the above metals.

[0032] As one specific implementation, the material of the transparent gate electrode layer 105 can be, for example, a transparent conductive material; the transparent conductive material may include at least one or a combination of transparent conductive oxide materials, thin-layer nanomaterials, and conductive polymer materials. Of course, the present invention is not limited thereto, and other types of materials for the transparent gate electrode layer 105 are also within the scope of protection of the present invention.

[0033] In a preferred embodiment, a second insulating layer 106 is further included between the substrate layer 101 and the channel layer 102, such as... Figure 5 As shown. The material of the second insulating layer 106 can be at least one or a combination of SiO2, Si3N4, Al2O3, HfO2, ZrO2, Ta2O5, and Y2O3. By providing the second insulating layer 106 between the substrate layer 101 and the channel layer 102, the parasitic leakage current channel between the channel layer 102 and the substrate layer 101 can be effectively isolated, thereby effectively reducing the parasitic leakage current of the substrate and improving the detection sensitivity of the phototransistor structure. At the same time, because of the isolation effect of the second insulating layer 106 on parasitic leakage current, the requirements of the substrate layer for the phototransistor structure can be relatively reduced. It is not necessary to use an intrinsic substrate or a high-resistivity substrate to achieve good leakage current suppression, thereby effectively reducing the manufacturing cost of the phototransistor structure.

[0034] A photodiode 20 exhibiting localized surface plasmon resonance (FSPR) is further disposed between the gate dielectric layer 103 and the transparent gate electrode layer 105 of the thin-film transistor. The photodiode 20 includes: The receiving layer 201 is formed on the gate dielectric layer 103 and is in contact with the gate dielectric layer 103.

[0035] In one specific implementation, the material of the receiving layer may be at least one or a combination of elemental semiconductor materials, oxide semiconductor materials, compound semiconductor materials, two-dimensional semiconductor materials, and organic semiconductor materials.

[0036] The excitation layer includes N metasurface unit structures 202, which are arrayed on the receiving layer 201, and each metasurface unit structure 202 forms a Schottky contact with the receiving layer 201; where N is a positive integer.

[0037] As one specific implementation, the material of the metasurface unit structure can be, for example, a single material or a composite material. The single material can be, for example, a metallic material, a metallic compound material, or a two-dimensional material; the composite material can include, for example, a combination of at least two of the following: metallic materials, metallic compound materials, and two-dimensional materials.

[0038] In one specific implementation, the cross-section of the metasurface unit structure 202 parallel to the channel layer 102 is a planar geometric shape or a periodic array pattern; wherein, the planar geometric shape can be, for example, a circle, square, rectangle, cross, double triangle, quadrangle, double ellipse, etc.; the periodic array pattern can be, for example, a grating array pattern. As an example, an example diagram of the cross-sectional pattern of the metasurface unit structure 202 array parallel to the channel layer 102 in the excitation layer is shown below. Figure 3 As shown. Of course, the present invention is not limited thereto, and other types of metasurface structures capable of generating surface plasmon resonance effects with cross-sectional patterns parallel to the channel layer 102 are also within the scope of protection of the present invention.

[0039] As a specific implementation method, the excitation layer can control the surface plasmon resonance response by adjusting the size, thickness, distribution period, duty cycle, and carrier concentration of the metasurface unit structure.

[0040] The first insulating layer 203 is formed on the receiving layer 201 and fills the spaces between adjacent metasurface unit structures 202, separating each metasurface unit structure 202, thereby preventing the local surface plasmon effect from being generated when the metasurface unit structures are connected together.

[0041] As an example, the material of the first insulating layer 203 may be at least one or a combination of SiO2, Si3N4, Al2O3, HfO2, ZrO2, Ta2O5, and Y2O3.

[0042] A transparent gate electrode layer 105 covers N metasurface unit structures 202 and a first insulating layer 203.

[0043] By setting an array of N metasurface unit structures (nanoscale) arranged with gaps and not connected on the surface of the receiving layer, when the incident light wave passes through the transparent gate electrode layer and irradiates the array of metasurface unit structures: The alternating electric field of incident light acts on the free carriers (electrons or holes) in the metasurface unit structure, causing them to deviate from their equilibrium positions and form collective coherent oscillations. Since the metasurface unit structure is a discrete, discontinuous nanoscale unit, the electron oscillations are strongly constrained by the structural boundaries and cannot propagate, but are confined to the interior of the metasurface unit structure and the near-field region. When the frequency of the incident light matches the oscillation frequency (incident light frequency = collective oscillation frequency of free carriers on the surface of the metasurface unit structure), localized surface plasmon resonance (LSPR) is excited. Subsequently, when the plasmons undergo Landau damping or electron scattering through nonradiative relaxation channels, they directly convert the resonance energy into high-energy electrons or holes, i.e., high-energy hot carriers. If the energy of the high-energy hot carriers is higher than the Schottky barrier height at the excitation-receiving layer interface, they can overcome the Schottky barrier at the excitation-receiving layer interface and be injected into the receiving layer, forming a photocurrent.

[0044] In one specific implementation, for example, the channel layer of the thin-film transistor is a depletion-type N-type channel, and the hot carrier type generated by the local surface plasmon resonance effect in the photodiode is hot electron type. When the thin-film transistor is working, a zero bias voltage or a small negative bias voltage is applied to the transparent gate electrode layer, so that the thin-film transistor is in the on or subthreshold on state. After illumination, the excitation layer generates a local surface plasmon resonance effect and generates hot electrons. The hot electrons cross the Schottky barrier at the excitation layer-receiving layer interface and reach the receiving layer, forming a thermal current, thereby changing the potential of the channel layer of the thin-film transistor, which is equivalent to reducing the gate voltage of the thin-film transistor, turning off the channel layer, and causing the source drain current to decrease exponentially. Thus, by measuring the change in the source drain current, the intensity of the incident light can be detected. This realizes the in-situ conversion of the optical signal into the gate voltage signal of the thin-film transistor. The weak hot carrier signal generated by the surface plasmon resonance effect can be exponentially amplified without the introduction of an external amplification circuit, thereby effectively improving the sensitivity and signal-to-noise ratio of the plasmonic photodetector.

[0045] Of course, this invention is not limited thereto. The detection method of the phototransistor structure can be flexibly adjusted according to the different types of hot carriers and channel layers generated by the local surface plasmon effect of the photodiode, as well as the type of thin film transistor operation by using hot carriers: for example, the channel layer of the thin film transistor is an enhancement-type N-channel, the type of hot carriers generated by the local surface plasmon effect of the photodiode is hot electron type, when the thin film transistor is working, a positive bias voltage or a small positive bias voltage is applied to the transparent gate electrode layer, so that the thin film transistor is in the on or subthreshold on state, and the hot electrons generated by the photodiode after illumination cause the thin film transistor to enter the subthreshold state or the off state; or other combinations of detection methods, such as the channel layer of the thin film transistor being a P-channel and the type of hot carriers generated by the local surface plasmon effect of the photodiode being hot hole type, are also within the protection scope of this invention.

[0046] In a preferred embodiment, the photodiode 20 further includes a reflective layer 204, such as... Figure 4 As shown, the reflective layer 204 is formed between the receiving layer 201 and the gate dielectric layer 103.

[0047] In a preferred embodiment, by providing a reflective layer 204 between the receiving layer 201 and the gate dielectric layer 103, the incident light can be reflected back to the excitation layer, further enhancing the local surface plasmon effect of the excitation layer, increasing the concentration of hot carriers, and thus effectively improving the sensitivity of the plasmon photodetector.

[0048] In one specific implementation, the reflective layer 204 can be, for example, a metal reflective layer or a Bragg reflective stack. The metal reflective layer can be, for example, a high-reflectivity elemental metal reflective layer, such as an Al or Ag reflective layer, or a high-reflectivity alloy reflective layer, such as an AlCu or AgAu reflective layer; the Bragg reflective stack can be, for example, a stack of Si3N4 / SiO2 or SiO2 / Si3N4 / SiO2 materials. Of course, the present invention is not limited to these, and other types of reflective layers are also within the scope of protection of the present invention.

[0049] According to an embodiment of the present invention, a photodetector array structure is also provided, comprising M phototransistor structures as described in the first aspect of the present invention, wherein M≥2, all phototransistor structures are connected along the X direction, Y direction or X / Y direction of a two-dimensional plane to form an array of m rows and n columns of phototransistor structures, wherein m and n are positive integers; the source of the phototransistor structure in each row is connected in series with the drain of the adjacent phototransistor structure to form a row of bit signal lines; the gates of all phototransistor structures in each column are connected in series to form a column of word signal lines.

[0050] As a specific implementation method, such as Figure 6 , Figure 7 As shown, the photoelectric detection array structure consists of M phototransistor structures as described in the first aspect of this invention, connected in series along the X / Y direction of a two-dimensional plane, forming an array of m rows and n columns, where m and n are positive integers. The direction of the rows is parallel to the channel direction of the phototransistors, and the direction of the columns is perpendicular to the channel direction of the phototransistors. The source of each phototransistor structure in a row is connected in series with the drain of the adjacent phototransistor structure, forming a row of bit signal lines. The source of the last phototransistor in each row is grounded. The gates of all phototransistor structures in each column are connected in series, forming a column of word signal lines. This achieves large-scale integration of phototransistor structures to meet the requirements of high-density, low-power, and fast-response photoelectric detection and imaging.

[0051] According to an embodiment of the present invention, a photoelectric detection method is also provided, which uses a photoelectric detection array structure as described in the second aspect of the present invention for photoelectric detection. Figure 8 As shown, the photoelectric detection method may include: S1: Apply a first voltage to all word signal lines in the photodetector array structure under background light illumination to turn on all phototransistor structures in the photodetector array structure and keep them in the on state.

[0052] As a specific implementation, for example, the channel type of the thin film transistor is a depletion-type N-channel, and the hot carrier type generated by the photodiode due to the local surface plasmon effect is hot electron type. The first voltage value is a positive bias voltage, and the first voltage value is greater than the threshold voltage value of the thin film transistor to ensure that all phototransistor structures in the photodetector array are turned on and remain in the on state. Due to the application of the positive bias voltage, most of the hot electrons generated by the photodiode under the background light are absorbed by the transparent electrode of the thin film transistor and are difficult to reach the receiving layer, thereby shielding the interference of the surface plasmon effect on the non-gated unit.

[0053] S2: Apply a second voltage to all bit signal lines in the photodetector array structure to generate source-drain current in each row bit signal line.

[0054] In one specific implementation, the second voltage is, for example, less than the difference between the first voltage and the thin-film transistor threshold voltage, which causes the phototransistor structure in the photodetector array structure to operate in the linear region.

[0055] S3: Apply a third voltage to the word signal line corresponding to the phototransistor structure to be selected in the photodetector array structure, so that the phototransistor structure to be selected is in the subthreshold operating region, and read the source-drain current value in the bit signal line corresponding to the phototransistor structure to be selected as the first current value.

[0056] In one specific implementation, the third voltage is, for example, zero bias or a small negative bias, so that the desired phototransistor structure is in the subthreshold operating region.

[0057] S4: Under the illumination of the probe light, read the source and drain current values ​​in the corresponding bit signal lines of the phototransistor structure to be selected as the second current value.

[0058] As a specific implementation method, under the illumination of the probe light, the excitation layer of the phototransistor structure to be selected generates a local surface plasmon effect and produces hot electrons. The hot electrons cross the Schottky barrier at the interface of the excitation layer and the receiving layer, reach the receiving layer, and form a thermal current, thereby changing the potential of the corresponding thin film transistor channel layer, causing the channel layer to turn off, thereby making the source and drain current of the bit signal line corresponding to the phototransistor structure to be selected decrease exponentially.

[0059] S5: Calculate the difference between the first current value and the second current value to obtain the photodetector signal of the desired selected phototransistor structure.

[0060] As an example, calculating the difference between the first current value and the second current value can be done by calculating the difference or ratio between the first current and the second current. Of course, this invention is not limited to this, and other methods for calculating the difference between the first current value and the second current value are also within the scope of this invention.

[0061] Those skilled in the art will understand that the embodiments provided by the present invention can be provided as methods, apparatus, or electronic devices. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A phototransistor structure, characterized in that, include: A thin-film transistor, the thin-film transistor comprising a substrate layer and a channel layer, a source / drain electrode layer, a gate dielectric layer and a transparent gate electrode layer sequentially formed on the substrate layer; as well as A photodiode is disposed between the gate dielectric layer and the transparent gate electrode layer; The photodiode exhibits a localized surface plasmon resonance effect; wherein, the photodiode comprises: A receiving layer is formed on the gate dielectric layer and is in contact with the gate dielectric layer; The excitation layer comprises N metasurface unit structures, which are arrayed on the receiving layer, and each metasurface unit structure forms a Schottky contact with the receiving layer; where N is a positive integer. A first insulating layer is formed on the receiving layer and fills the spaces between adjacent metasurface unit structures, separating each metasurface unit structure. The transparent gate electrode layer covers the N metasurface unit structures and the first insulating layer.

2. The phototransistor structure according to claim 1, characterized in that, The material of the metasurface unit structure is a single material or a composite material; The single material is a metallic material, a metallic compound material, or a two-dimensional material; the composite material includes a combination of at least two of the following: metallic materials, metallic compound materials, and two-dimensional materials.

3. The phototransistor structure according to claim 1, characterized in that, The metasurface unit structure is parallel to the cross-section of the channel layer and has a planar geometric shape or a periodic array pattern.

4. The phototransistor structure according to claim 1, characterized in that, The photodiode further includes a reflective layer formed between the receiving layer and the gate dielectric layer.

5. The phototransistor structure according to claim 4, characterized in that, The reflective layer is a metallic reflective layer or a Bragg reflective stack.

6. The phototransistor structure according to claim 1, characterized in that, The material of the receiving layer is at least one or a combination of elemental semiconductor materials, oxide semiconductor materials, compound semiconductor materials, two-dimensional materials, and organic semiconductor materials.

7. The phototransistor structure according to claim 1, characterized in that, The material of the first insulating layer is at least one or a combination of SiO2, Si3N4, Al2O3, HfO2, ZrO2, Ta2O5, and Y2O3.

8. The phototransistor structure according to claim 1, characterized in that, The substrate layer and the channel layer further include a second insulating layer; the material of the second insulating layer is at least one or a combination of SiO2, Si3N4, Al2O3, HfO2, ZrO2, Ta2O5, and Y2O3.

9. A photoelectric detection array structure, characterized in that, The photodetector array structure includes M phototransistor structures as described in any one of claims 1 to 8, wherein M ≥ 2, and all phototransistor structures are connected along the X direction, Y direction, or X / Y direction of a two-dimensional plane to form an array of m rows and n columns of phototransistor structures, where m and n are positive integers; the source of the phototransistor structure in each row is connected in series with the drain of the adjacent phototransistor structure to form a row of bit signal lines; the gates of all phototransistor structures in each column are connected in series to form a column of word signal lines.

10. A photoelectric detection method, characterized in that, Photoelectric detection using the photoelectric detection array structure as described in claim 9 includes: Under background light illumination, a first voltage is applied to all word signal lines in the photodetector array structure to turn on and keep all phototransistor structures in the photodetector array structure in the on state. A second voltage is applied to all bit signal lines in the photodetector array structure to generate source-drain current in each row bit signal line; A third voltage is applied to the word signal line corresponding to the phototransistor structure to be selected in the photodetector array structure, so that the phototransistor structure to be selected is in the subthreshold operating region, and the source-drain current value in the bit signal line corresponding to the phototransistor structure to be selected is read as the first current value. Under the illumination of the probe light, the source and drain current values ​​in the corresponding bit signal lines of the phototransistor structure to be selected are read as the second current value. The difference between the first current value and the second current value is calculated to obtain the photodetector signal of the desired selected phototransistor structure.

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