Broadband self-driven photoelectric detector and preparation method thereof

Abstract

The invention relates to a broadband self-driven photoelectric detector and a preparation method thereof, and belongs to the technical field of semiconductor photoelectric devices. The photoelectric detector comprises an n-GaAs substrate layer, a Sb2S3 layer, a PEDOT: PSS thin film layer and a transparent substrate layer which are sequentially arranged in a stacked mode. The n-GaAs substrate layer and the Sb2S3 layer are attached to form a heterojunction; the n-GaAs substrate layer and the PEDOT: PSS thin film layer are arranged in a staggered manner, and the overlapped region of the n-GaAs substrate layer and the PEDOT: PSS thin film layer completely One side, close to the Sb2S3 layer, of the n-GaAs substrate layer is provided with a first electrode, one side, close to the Sb2S3 layer, of the PEDOT: PSS thin film layer is provided with a second electrode, and the first electrode is arranged in an area which is not overlapped with the PEDOT: PSS thin film layer and is far away from the second electrode. According to the broadband self-driven photoelectric detector provided by the invention, the high-conductivity transparent PEDOT: PSS thin film is adopted as an incident window of detection light, so that the transmittance of the incident light is improved, and the collection of photon-generated carriers is promoted; and the absorption peak values of the Sb2S3 microwire and the GaAs correspond to different spectral ranges, so that a broadband optical detection function is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor optoelectronic devices and relates to a wide-band self-driven photoelectric detector and a preparation method thereof. Background Art

[0002] The significance of wide-band photodetectors lies in their ability to cover a wide range of wavelengths from ultraviolet to visible light to infrared, which makes them of great application value in many fields. For example, wide-band detectors can be used in military reconnaissance and security monitoring, and can effectively detect and identify targets under different lighting conditions, which is crucial to improving battlefield situation awareness and security protection capabilities.

[0003] With the development of optoelectronic technology, wide-band photodetectors are gradually developing towards low cost, low energy consumption or no energy consumption, high performance, and miniaturization. However, wide bandgap materials (such as GaN and ZnO) usually have good light response in the ultraviolet band, but almost no light response in the visible and infrared bands due to insufficient light absorption; narrow bandgap materials (such as GaAs and InP) have response in a wide band, but the response is weak in the ultraviolet and visible bands, and strong in the near-infrared band. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a wide-band self-driven photodetector and a preparation method thereof, which can achieve high-performance wide-band photodetection by designing a composite heterojunction structure.

[0005] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0006] On the one hand, the present invention provides a wide-band self-driven photodetector, comprising: an n-GaAs substrate layer, a Sb2S3 layer, a PEDOT:PSS thin film layer and a transparent substrate layer stacked in sequence;

[0007] The n-GaAs substrate layer and the Sb2S3 layer are bonded together to form a heterojunction;

[0008] The n-GaAs substrate layer and the PEDOT:PSS thin film layer are staggered, and the overlapping area of ​​the two completely covers the Sb2S3 layer;

[0009] A first electrode is provided on the side of the n-GaAs substrate layer close to the Sb2S3 layer, and a second electrode is provided on the side of the PEDOT:PSS thin film layer close to the Sb2S3 layer, wherein the first electrode is provided in a region that does not overlap with the PEDOT:PSS thin film layer and is far away from the second electrode.

[0010] Furthermore, a PDMS layer is provided between the n-GaAs substrate layer and the PEDOT:PSS thin film layer, so that the n-GaAs substrate layer and the PEDOT:PSS thin film layer are not in contact with each other.

[0011] Furthermore, the size of the n-GaAs substrate layer is 10 mm×40 mm, the thickness is 300 μm, and the doping concentration is 2.1×10 19 cm -3 , the electron mobility is 1200 cm 2 / V·s.

[0012] Furthermore, the Sb2S3 layer has a Sb2S3 microwire with a height of 10 μm to 20 μm, a width of 10 μm to 20 μm, a length of 5 mm to 20 mm, and a hole concentration of 10 12 cm -3 Up to 10 14 cm -3 , the hole mobility is 1 cm 2 / V·s to 10cm 2 / V·s.

[0013] Furthermore, the PEDOT:PSS thin film layer is spin-coated on the transparent substrate layer.

[0014] Furthermore, the material of the transparent substrate layer includes SiO2.

[0015] Furthermore, the length of the PEDOT:PSS thin film layer is 40 mm, the width is 10 mm, the thickness is 10 μm, and the carrier concentration is 1×10 18 cm -3 .

[0016] Further, the material of the first electrode is Ni / Au, and the material of the second electrode is Ti / Au;

[0017] The first electrode has a size of 10 mm×5 mm, a total thickness of 150 nm, a Ni thickness of 50 nm, and an Au thickness of 100 nm;

[0018] The second electrode has a size of 10 mm×5 mm, a total thickness of 130 nm, a Ti thickness of 30 nm, and an Au thickness of 100 nm.

[0019] On the other hand, the present invention also provides a method for preparing a wide-band self-driven photoelectric detector, comprising:

[0020] The Sb2S3 layer was prepared by a hydrothermal method;

[0021] The PEDOT:PSS thin film layer is prepared on the transparent substrate layer by spin coating;

[0022] Annealing the n-GaAs substrate layer;

[0023] The second electrode is deposited on the PEDOT:PSS thin film layer and the first electrode is deposited on the n-GaAs substrate layer by electron beam evaporation.

[0024] The Sb2S3 layer is closely attached to the n-GaAs substrate layer on which the first electrode is plated, and the PDMS layer is attached to both sides of the Sb2S3 layer;

[0025] The PEDOT:PSS film layer coated with the second electrode is tightly attached to the Sb2S3 layer, and then placed in an oven to dry.

[0026] Furthermore, a PEDOT:PSS thin film layer is prepared on the transparent substrate layer by a spin coating method, comprising:

[0027] The concentration used is 5 mg mL -1 The PEDOT:PSS solution was spin-coated at 2000 rpm for 3 to 5 times, each time for 2 minutes;

[0028] After the spin coating was completed, the PEDOT:PSS film layer was placed on a heating stage and heated to 50 °C for 1 hour.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The present invention proposes a wide-band self-driven photodetector, which realizes effective separation of photogenerated carriers by forming an effective heterojunction structure between n-type GaAs and a single Sb2S3 micron wire, so that the device can work under zero bias conditions; at the same time, the absorption peaks of the Sb2S3 micron wire and GaAs correspond to different spectral ranges, so that the photodetector realizes a high-response wide-band light detection function. The highly conductive transparent PEDOT:PSS film is used as the incident window of the detection light, which improves the transmittance of the incident light and promotes the collection of photogenerated carriers. The present invention not only improves the performance of the photodetector, but also broadens its application in wide-band detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic diagram of the structure of a wide-band self-driven photodetector provided by an embodiment of the present invention;

[0032] Figure 2 A schematic structural diagram of a wide-band self-driven photoelectric detector from another angle provided by an embodiment of the present invention;

[0033] Figure 3 A spectral responsivity curve of a wide-band self-driven photodetector under zero bias provided by an embodiment of the present invention;

[0034] Figure 4 A schematic flow chart of a method for preparing a wide-band self-driven photodetector provided by an embodiment of the present invention;

[0035] In the figure: 1-Sb2S3 layer, 2-transparent substrate layer, 3-PEDOT:PSS thin film layer, 4-n-GaAs substrate layer, 5-PDMS layer, 6-second electrode, 7-first electrode. DETAILED DESCRIPTION

[0036] The technical solution of the present invention is described in detail below through the accompanying drawings and specific embodiments. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. The embodiments of the present application and the specific features in the embodiments are detailed descriptions of the technical solution of the present application, rather than limitations on the technical solution of the present application. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments can be combined with each other.

[0037] The term "and / or" herein is only a description of the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " herein generally indicates that the front and back associated objects are in an "or" relationship. The orientation or position relationship indicated by the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "inside", "outside", etc. is based on the orientation or position relationship shown in the accompanying drawings, and is only used to explain the relative position relationship, movement, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly. It is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present disclosure / application.

[0038] In addition, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the feature. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0039] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood by specific circumstances.

[0040] Embodiment 1:

[0041] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a wide-band self-driven photodetector, wherein: Figure 2 for Figure 1 The photodetector structure of the present invention comprises an n-GaAs substrate layer 4, a Sb2S3 layer 1, a PEDOT:PSS thin film layer 3 and a transparent substrate layer 2 which are stacked in sequence.

[0042] Among them, the n-GaAs substrate layer 4 and the Sb2S3 layer 1 are bonded to form a heterojunction; the n-GaAs substrate layer 4 and the PEDOT:PSS thin film layer 3 are staggered, and the overlapping area of ​​the two completely covers the Sb2S3 layer 1; a first electrode 7 is provided on the side of the n-GaAs substrate layer 4 close to the Sb2S3 layer 1, and a second electrode 6 is provided on the side of the PEDOT:PSS thin film layer 3 close to the Sb2S3 layer 1, wherein the first electrode 7 is provided in an area that does not overlap with the PEDOT:PSS thin film layer 3 and is far away from the second electrode 6.

[0043] The present invention realizes effective separation of photogenerated carriers by forming an effective heterojunction structure between n-type GaAs and a single Sb2S3 micron wire, so that the device can operate under zero bias conditions; at the same time, the Sb2S3 micron wire and the GaAs absorption peaks correspond to different spectral ranges, so that the photodetector realizes a high-responsivity wide-band light detection function.

[0044] PDMS layers 5 are respectively arranged between the n-GaAs substrate layer 4 and the PEDOT:PSS film layer 3 and on both sides of the Sb2S3 layer 1 to separate the n-GaAs substrate layer 4 and the PEDOT:PSS film layer 3 so that their edges do not touch each other.

[0045] The thickness of the PDMS layer 5 is thinner than that of the Sb2S3 layer 1 to ensure that the Sb2S3 layer 1 and the PEDOT:PSS film layer 3 are in close contact.

[0046] In the embodiment of the present invention, the overlapping direction of the n-GaAs substrate layer 4, the Sb2S3 layer 1, the PEDOT:PSS thin film layer 3 and the transparent substrate layer 2 is used as the thickness direction.

[0047] The material of the n-GaAs substrate layer 4 is n-type gallium arsenide, with a size of 10 mm×40 mm, a thickness of 300 μm, and a doping concentration of 2.1×10 19 cm -3 , the electron mobility is 1200 cm 2 / V·s.

[0048] The material of the Sb2S3 layer 1 is antimony trisulfide, and the Sb2S3 microwires used therein have a height of 10 μm to 20 μm, a width of 10 μm to 20 μm, a length of 5 mm to 20 mm, and a hole concentration of 10 12 cm -3 Up to 10 14 cm -3 , the hole mobility is 1 cm 2 / V·s to 10 cm 2 / V·s.

[0049] The material of the PEDOT:PSS film layer 3 is PEDOT:PSS, which is a high molecular polymer aqueous solution composed of two substances, PEDOT and PSS. PEDOT is a polymer of EDOT (3,4-ethylenedioxythiophene monomer), and PSS is polystyrene sulfonate. The combination of PEDOT and PSS greatly improves the solubility of PEDOT, making it exhibit excellent conductive properties in aqueous solution.

[0050] The present invention uses a highly conductive transparent PEDOT:PSS film as an incident window for the detection light, which improves the transmittance of the incident light and promotes the collection of photogenerated carriers. Therefore, the PEDOT:PSS film layer 3 requires a transparent substrate layer as support. The transparent substrate layer 2 of the present invention is made of quartz, and the PEDOT:PSS film layer 3 is spin-coated on the transparent substrate layer 2.

[0051] Specifically, the length of the PEDOT:PSS thin film layer 3 in the embodiment of the present invention is 40 mm, the width is 10 mm, the thickness is 10 μm, and the carrier concentration is 1×10 18 cm -3 .

[0052] The first electrode 7 is made of Ni / Au, and the second electrode 6 is made of Ti / Au.

[0053] Among them, the size of the first electrode 7 is 10 mm×5 mm, the total thickness is 150 nm, the Ni thickness is 50 nm, and the Au thickness is 100 nm; the size of the second electrode 6 is 10 mm×5 mm, the total thickness is 130 nm, the Ti thickness is 30 nm, and the Au thickness is 100 nm.

[0054] The length, width and thickness dimensions of the above-mentioned n-GaAs substrate layer 4, Sb2S3 layer 1, PEDOT:PSS thin film layer 3, first electrode 7 and second electrode 6 are used to more intuitively display the structural details of the photodetector of the present invention and are not restrictive.

[0055] Lead wires are drawn from the first electrode 7 and the second electrode 6 at both ends of the photodetector, and bias voltage is applied to test the spectral responsivity of the wide-band self-driven photodetector of the present invention. Figure 3 It can be seen from the test results shown that the photodetector of the present invention exhibits high responsiveness in the wavelength range of 350 nm to 1000 nm, and can achieve light detection covering ultraviolet light, visible light, near infrared light, etc.

[0056] Embodiment 2:

[0057] like Figure 4 As shown, the embodiment of the present invention provides a method for preparing a wide-band self-driven photodetector, and the method can prepare the wide-band self-driven photodetector described in Example 1. This flowchart only shows the logical sequence of the method described in this embodiment. Under the premise of no conflict, in other possible embodiments of the present invention, different methods can be used. Figure 4 The steps shown or described are completed in the order shown. The method specifically comprises the following steps:

[0058] Step 1: Prepare Sb2S3 layer 1 by hydrothermal method;

[0059] Take 4 g of thiourea and 10 g of antimony pentoxide as reaction precursors, dissolve the two in 100 g of water and stir thoroughly; put the mixed solution into a reactor, heat the temperature to 230 °C, and maintain it for 20 hours; after natural cooling, obtain the Sb2S3 sample, wash it with anhydrous ethanol three times, and put it into a drying cabinet at 80 °C to dry.

[0060] Step 2: preparing a PEDOT:PSS thin film layer 3 on the transparent substrate layer 2 by spin coating;

[0061] Place a clean transparent substrate layer 2 with a length of 4 cm and a width of 1 cm on a spin coater and start the spin coater. Set the spin coater speed to 2000 rpm for 2 minutes. Use a pipette to pipette a solution with a concentration of 5 mg mL -1The PEDOT:PSS solution was dropped onto the transparent substrate layer 2; the above spin coating step was repeated 5 times; after completion, the sample was placed on a heating stage, heated to 50 °C, and maintained for 1 hour.

[0062] Step 3: annealing the n-GaAs substrate layer 4;

[0063] Cut out an n-GaAs substrate layer 4 with a length of 4 cm and a width of 1 cm; put the n-GaAs substrate layer 4 into a trichloroethylene solution, an acetone solution, and deionized water for ultrasonic cleaning for 8 minutes; put it into an oven for drying, take it out after 20 minutes, and blow it dry with nitrogen; heat the tube furnace to 500°C, then put the clean n-GaAs substrate layer 4 in the tube furnace, keep it for 30 minutes, take out the n-GaAs substrate layer 4 and cool it naturally.

[0064] Step 4: using electron beam evaporation to deposit the second electrode 6 on the PEDOT:PSS thin film layer 3 and the first electrode 7 on the n-GaAs substrate layer 4;

[0065] The transparent substrate layer 2 containing the PEDOT:PSS thin film layer 3 and the n-GaAs substrate layer 4 were covered by a mask, leaving an unobstructed area with a length of 0.5 cm and a width of 1 cm. The vacuum degree of the electron beam vacuum chamber was pumped to 10 -4 Pa, put Ti metal source and Au metal source respectively, and evaporate 30 nm Ti electrode and 100 nm Au electrode in the unblocked area of ​​​​the PEDOT:PSS thin film layer 3; then put Ni metal source and Au metal source respectively, and evaporate 50 nm Ni electrode and 100 nm Au electrode in the unblocked area of ​​​​the n-GaAs substrate layer 4.

[0066] Step 5: The Sb2S3 layer 1 is closely attached to the n-GaAs substrate layer 4 coated with the first electrode 7, and the PDMS layer 5 is attached to both sides of the Sb2S3 layer 1;

[0067] Use tweezers to take out a 1 cm long Sb2S3 micron ribbon and place it on the n-GaAs substrate layer 4. Operate the Sb2S3 micron wire under a microscope to ensure that the Sb2S3 micron wire and the n-GaAs substrate layer 4 are tightly fitted and have no contact with the first electrode 7. Then, PDMS thin film layers 5 with the same thickness as the Sb2S3 micron wire are attached to both sides of the Sb2S3 micron wire on the n-GaAs substrate layer 4.

[0068] Step 6: The PEDOT:PSS thin film layer 3 coated with the second electrode 6 is tightly attached to the Sb2S3 layer 1, and then the device is placed in an oven to dry.

[0069] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of this disclosure / application.

Claims

1. A broadband self-driven photodetector, characterized in that: It includes an n-GaAs substrate layer, a Sb2S3 layer, a PEDOT:PSS thin film layer and a transparent substrate layer which are stacked in sequence; The n-GaAs substrate layer and the Sb2S3 layer are bonded together to form a heterojunction; The n-GaAs substrate layer and the PEDOT:PSS thin film layer are staggered, and the overlapping area of ​​the two completely covers the Sb2S3 layer; A first electrode is provided on the side of the n-GaAs substrate layer close to the Sb2S3 layer, and a second electrode is provided on the side of the PEDOT:PSS thin film layer close to the Sb2S3 layer, wherein the first electrode is provided in a region that does not overlap with the PEDOT:PSS thin film layer and is far away from the second electrode.

2. The broadband self-driven photodetector according to claim 1, characterized in that: A PDMS layer is arranged between the n-GaAs substrate layer and the PEDOT:PSS thin film layer, so that the n-GaAs substrate layer and the PEDOT:PSS thin film layer are not in contact with each other.

3. The broadband self-driven photodetector according to claim 1, characterized in that: The size of the n-GaAs substrate layer is 10 mm×40 mm, the thickness is 300 mm, and the doping concentration is 2.1×10 19 cm -3 , the electron mobility is 1200 cm 2 / V·s.

4. The broadband self-driven photodetector according to claim 1, characterized in that: The Sb2S3 layer uses Sb2S3 microwires with a height of 10 mm to 20 mm, a width of 10 mm to 20 mm, a length of 5 mm to 20 mm, and a hole concentration of 10 12 cm -3 Up to 10 14 cm -3 , the hole mobility is 1 cm 2 / V·s to 10 cm 2 / V·s.

5. The broadband self-driven photodetector according to claim 1, characterized in that: The PEDOT:PSS thin film layer is spin-coated on the transparent substrate layer.

6. The broadband self-driven photodetector according to claim 5, characterized in that: The material of the transparent substrate layer includes SiO2.

7. The broadband self-driven photodetector according to claim 5, characterized in that: The length of the PEDOT:PSS thin film layer is 40 mm, the width is 10 mm, the thickness is 10 mm, and the carrier concentration is 1×10 18 cm -3 .

8. The broadband self-driven photodetector according to claim 1, characterized in that: The material of the first electrode is Ni / Au, and the material of the second electrode is Ti / Au; The first electrode has a size of 10 mm×5 mm, a total thickness of 150 nm, a Ni thickness of 50 nm, and an Au thickness of 100 nm; The second electrode has a size of 10 mm×5 mm, a total thickness of 130 nm, a Ti thickness of 30 nm, and an Au thickness of 100 nm.

9. A method for preparing a wide-band self-driven photodetector, characterized in that: include: The Sb2S3 layer was prepared by a hydrothermal method; The PEDOT:PSS thin film layer is prepared on the transparent substrate layer by spin coating; Annealing the n-GaAs substrate layer; The second electrode is deposited on the PEDOT:PSS thin film layer and the first electrode is deposited on the n-GaAs substrate layer by electron beam evaporation. The Sb2S3 layer is closely attached to the n-GaAs substrate layer on which the first electrode is plated, and the PDMS layer is attached to both sides of the Sb2S3 layer; The PEDOT:PSS film layer coated with the second electrode is tightly attached to the Sb2S3 layer, and then placed in an oven to dry.

10. The method for preparing a wide-band self-driven photodetector according to claim 9, characterized in that: The PEDOT:PSS thin film layer is prepared on the transparent substrate layer by spin coating, including: The concentration used is 5 mg mL -1 The PEDOT:PSS solution was spin-coated at 2000 rpm for 3 to 5 times, each time for 2 minutes; After the spin coating was completed, the PEDOT:PSS film layer was placed on a heating stage and heated to 50 °C for 1 hour.

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