Self-powered ultraviolet photoelectric detector based on GaN / CuI heterojunction, preparation method of self-powered ultraviolet photoelectric detector and low-power-consumption ultraviolet communication system

Abstract

The invention discloses a self-powered ultraviolet photoelectric detector based on a GaN / CuI heterojunction, a preparation method thereof and a low-power-consumption ultraviolet communication system, the self-powered ultraviolet photoelectric detector is based on a heterojunction structure formed by an n-type GaN thin film layer and a CuI thin film layer, the response speed of the heterojunction is high, the stability is high, and a self-powered light detection mode can be realized. The system comprises an ultraviolet light source, an optical signal receiver, a data acquisition module and a decoding module, wherein the data acquisition module consists of a power supply module, an amplifying circuit and a high-precision ampere meter. The decoding module is composed of an analog-to-digital converter and a single-chip microcomputer development board, a GaN / CuI heterojunction photoelectric detector is used as an optical signal receiver, and the characteristics of low power consumption, high confidentiality and high flexibility are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of wide bandgap semiconductor optoelectronic devices and optical communication technology, and specifically relates to a self-powered ultraviolet photodetector based on a GaN / CuI heterojunction, a preparation method thereof, and a low-power ultraviolet light communication system. Background Art

[0002] With the rapid development of wireless communication technology, ultraviolet light communication, as an emerging short-distance high-data-rate transmission solution, has gradually attracted widespread attention. Compared with traditional radio wave communication, ultraviolet light communication can provide low-latency, low-interference and high-security communication services.

[0003] Ultraviolet photodetectors can identify light signals in the 10-400nm band and are widely used in deep space detection, fire monitoring, and corona monitoring. In particular, ultraviolet photodetectors can convert ultraviolet light signals into electrical signals and are key components of ultraviolet communication systems. Therefore, the development of high-performance ultraviolet photodetectors is an essential part of ultraviolet communication technology.

[0004] At present, the commonly used ultraviolet light communication system needs to apply an external bias voltage to the optical signal receiver when working, so there are problems of high power consumption and complex equipment. It also exhibits conservative photoelectric performance and a narrow ultraviolet response band, which limits its popularization and promotion in practical applications. Summary of the invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0006] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0007] Therefore, the object of the present invention is to overcome the deficiencies in the prior art and provide a self-powered ultraviolet photodetector based on GaN / CuI heterojunction.

[0008] In order to solve the above technical problems, the present invention provides the following technical solution: the structure of the self-powered ultraviolet photoelectric detector from bottom to top includes:

[0009] Sapphire substrate layer 100;

[0010] An n-type GaN thin film layer 200, and a first electrode 400 in ohmic contact with the n-type GaN thin film layer 200;

[0011] A p-type CuI thin film layer 300 and a second electrode 500 in ohmic contact with the p-type CuI thin film layer 300.

[0012] As a preferred solution of the self-powered ultraviolet photodetector based on GaN / CuI heterojunction described in the present invention, the thickness of the n-type GaN thin film layer 200 is 100nm~10μm, and the thickness of the p-type CuI thin film layer 300 is 10~500nm.

[0013] As a preferred solution of the self-powered ultraviolet photodetector based on GaN / CuI heterojunction described in the present invention, the first electrode 400 and the second electrode 500 are both metal electrodes, including one or more of aluminum, copper, silver, platinum, titanium, indium, and gold.

[0014] The purpose of the present invention is to provide a method for preparing a self-powered ultraviolet photodetector based on a GaN / CuI heterojunction.

[0015] In order to solve the above technical problems, the present invention provides the following technical solutions: comprising:

[0016] A GaN thin film is prepared on the sapphire substrate layer 100 by an organic chemical vapor deposition method to form an n-type GaN thin film layer 200;

[0017] Spin-coat a layer of CuI precursor solution on the semi-covered GaN film by spin coating, heat it on a heating stage to form a p-type CuI thin film layer 300, and then obtain a GaN / CuI heterojunction;

[0018] Metal circles are prepared on the surfaces of the n-type GaN thin film layer 200 and the p-type CuI thin film layer 300 to form a first electrode 400 and a second electrode 500, respectively, to obtain a GaN / CuI heterojunction ultraviolet photodetector.

[0019] As a preferred scheme of the preparation method of the self-powered ultraviolet photodetector based on GaN / CuI heterojunction described in the present invention, wherein: the organic chemical vapor deposition method, wherein the gallium source is trimethylgallium, the nitrogen source is ammonia, the carrier gas is nitrogen, and the nitrogen flow rate is 250-350sccm.

[0020] As a preferred scheme of the preparation method of the self-powered ultraviolet photodetector based on GaN / CuI heterojunction described in the present invention, the concentration of the CuI precursor solution is 20-60 mg / ml, wherein the solute is CuI powder, and the solvent is a mixed solution of chlorobenzene and dipropyl sulfide in a volume ratio of 18-20:1.

[0021] As a preferred solution of the method for preparing the self-powered ultraviolet photodetector based on GaN / CuI heterojunction described in the present invention, the heating time on the hot stage is 8 to 12 minutes, and the heating temperature is 90 to 110°C.

[0022] Another object of the present invention is to provide a low power consumption ultraviolet light communication system.

[0023] In order to solve the above technical problems, the present invention provides the following technical solutions: comprising:

[0024] Ultraviolet light source, emitting ultraviolet light in the range of 200 to 400 nm;

[0025] An optical signal receiver, using the self-powered ultraviolet photodetector described in claim 1;

[0026] The data acquisition module consists of a power supply, an amplifier circuit, and a high-precision ammeter;

[0027] The decoding module consists of an analog-to-digital converter and a microcontroller development board.

[0028] As a preferred solution of the low-power ultraviolet communication system of the present invention, wherein: the power supply is a high-precision AC-DC linear power supply, which can realize 220V to ±5V conversion, and the ripple is less than 1mV;

[0029] The amplifier circuit is a differential amplifier circuit, which is used to reasonably amplify the electrical signal for subsequent processing;

[0030] The high-precision ammeter has a measurement range of 0 to 3A and a resolution of 0.1μA;

[0031] The decoding module, wherein the analog-to-digital converter is used to convert the current signal into a discrete digital signal; the single-chip microcomputer development board with the relevant program burned is used to display the digital signal

[0032] Another object of the present invention is to provide a working procedure of a low power consumption ultraviolet light communication system.

[0033] In order to solve the above technical problems, the present invention provides the following technical solutions: comprising:

[0034] The ultraviolet light source modulates the light signal with the on-off state of light, generating a light signal wave with coded information, where on is the "1" state and off is the "0" state;

[0035] The GaN / CuI heterojunction self-powered UV photodetector acts as an optical signal receiver, detecting the transmitted optical signal wave with coded information and converting it into an electrical signal of the same frequency;

[0036] Among them, due to the photovoltaic effect of GaN / CuI heterojunction, the optical signal receiver based on GaN / CuI heterojunction ultraviolet photodetector can achieve self-powered operation under zero volt bias;

[0037] The data acquisition module amplifies and reads the electrical signal converted by the GaN / CuI heterojunction optical receiver;

[0038] The decoding module is responsible for converting the electrical signal into a digital signal and displaying it through the digital tube on the microcontroller development board.

[0039] Beneficial effects of the present invention:

[0040] The present invention uses a high-performance GaN / CuI heterojunction self-powered photodetector as an optical signal receiver. Based on the combination of GaN and CuI, a typical type II heterojunction is formed, which exhibits an obvious photovoltaic effect, can achieve a wide spectral response in the UVA and UVC bands, and has very excellent photoelectric performance.

[0041] GaN / CuI heterojunction UV photodetectors are used as optical signal receivers in UV communication systems. Since GaN / CuI heterojunction UV photodetectors can identify UVA and UVC dual-band UV light signals, the system provides a powerful solution for current and future data transmission with its low power consumption, high transmission rate, wide spectrum response, and strong security.

[0042] Since ultraviolet light attenuates faster than visible light and infrared light when propagating in the atmosphere, it is more difficult to be intercepted or interfered with. Therefore, the ultraviolet communication system based on GaN / CuI heterojunction ultraviolet photodetector provides higher security and privacy protection for data transmission, which is very suitable for communication environments that require confidentiality. It can achieve low power consumption of ultraviolet communication system and is in line with the current "dual carbon" development strategy. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0044] Figure 1 Schematic diagram of the structure of the GaN / CuI heterojunction ultraviolet photodetector according to Example 1 of the present invention.

[0045] Figure 2 The current-voltage curves of the GaN / CuI heterojunction ultraviolet photodetector of Example 1 of the present invention under dark, 254nm and 365nm ultraviolet light.

[0046] Figure 3 Light response curve of the GaN / CuI heterojunction photodetector according to Example 1 of the present invention under zero bias as the intensity of 365 nm light changes.

[0047] Figure 4 This is a flow chart of a low-power ultraviolet communication system based on a GaN / CuI heterojunction self-powered detector according to Example 2 of the present invention.

[0048] Figure 5 It is the photoresponse current of the GaN / CuI heterojunction self-powered ultraviolet photodetector of Example 2 of the present invention under regular switching irradiation of a 365nm ultraviolet light source.

[0049] Figure 6 Light response curve of the GaN / CuI heterojunction photodetector according to Example 3 of the present invention under zero bias as the intensity of 365 nm light changes.

[0050] Figure 7 Light response curve of the GaN / CuI heterojunction photodetector of Example 4 of the present invention as the intensity of 365nm light changes under zero bias. DETAILED DESCRIPTION

[0051] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0052] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0053] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0054] Unless otherwise specified, the raw materials used in the present invention are all commercially available in the art.

[0055] Example 1

[0056] This embodiment provides a self-powered ultraviolet photodetector based on GaN / CuI heterojunction and a preparation method thereof, referring to Figure 1The detector has the following structure: a sapphire substrate 100, an n-type GaN film 200, a p-type CuI film 300, a first electrode 400 in ohmic contact with GaN, and a second electrode 500 in ohmic contact with CuI. The specific preparation method is as follows:

[0057] 1) A GaN film with a thickness of 4 μm was prepared on a (0001) oriented sapphire (Al2O3) substrate by metal organic chemical vapor deposition, wherein the gallium source was trimethylgallium, the nitrogen source was ammonia, the carrier gas was nitrogen, and the nitrogen flow rate was 300 sccm;

[0058] 2) Using CuI powder as the solute and a mixed solution of chlorobenzene and dipropyl sulfide in a volume ratio of 19:1 as the solvent, a 50 mg / ml CuI precursor solution was prepared, and a layer of CuI solution was spin-coated on the semi-covered GaN film by spin coating, and heated on a heating table at 100°C for 10 minutes to obtain a GaN / CuI heterojunction. The thickness of the CuI film here is 60 nm;

[0059] 3) A circular indium electrode with a diameter of 1 mm was prepared on the GaN and CuI surfaces at a distance of 1 mm, respectively, to obtain a GaN / CuI heterojunction ultraviolet photodetector.

[0060] The GaN / CuI heterojunction prepared by the present invention was tested by Keysight B1505A power device analyzer in the dark, under 254nm and 365nm ultraviolet light irradiation, and the current-voltage curves were as follows: Figure 2 It is shown that the GaN / CuI heterojunction photodetector prepared according to the present invention is a self-powered ultraviolet photodetector with excellent performance.

[0061] Figure 3 The light response curve of the GaN / CuI heterojunction photodetector under zero bias with the change of 365nm light intensity shows that the responsivity and detection rate of the GaN / CuI heterojunction photodetector in this embodiment are 228mA / W and 4.3×10 13 Jones.

[0062] Example 2

[0063] Reference Figure 4 This embodiment provides a low-power ultraviolet communication system based on a GaN / CuI heterojunction self-powered detector, specifically:

[0064] It consists of an ultraviolet light source, an optical signal receiver, a data acquisition module, and a decoding module, among which:

[0065] The ultraviolet light emitted by the ultraviolet light source has a wavelength range of 200 to 400 nm;

[0066] The optical signal receiver is a self-powered ultraviolet photodetector based on the GaN / CuI heterojunction prepared in Example 1;

[0067] The data acquisition module consists of a power supply, an amplifier circuit, and a high-precision ammeter;

[0068] Furthermore, the power supply is a high-precision AC-DC linear power supply, which can realize 220V to ±5V conversion with a ripple of less than 1mV; the amplifier circuit is a differential amplifier circuit, which is used to reasonably amplify the electrical signal for subsequent processing; the high-precision ammeter has a measurement range of 0 to 3A and a resolution of 0.1μA

[0069] The decoding module consists of an analog-to-digital converter and a microcontroller development board;

[0070] Furthermore, the analog-to-digital converter is used to convert the current signal into a discrete digital signal; and the single-chip microcomputer development board with the relevant program burned is used to display the digital signal.

[0071] The working steps are as follows:

[0072] S1: The ultraviolet light source modulates the optical signal with the on-off state of light to generate an optical signal wave with coded information, where on is the "1" state and off is the "0" state;

[0073] S2: GaN / CuI heterojunction self-powered ultraviolet photodetector is used as an optical signal receiver to detect the transmitted optical signal wave with coded information and convert it into an electrical signal of the same frequency. Due to the photovoltaic effect of GaN / CuI heterojunction, the optical signal receiver based on GaN / CuI heterojunction ultraviolet photodetector can achieve self-powered operation under zero volt bias.

[0074] S3: The data acquisition module amplifies and reads the electrical signal converted by the GaN / CuI heterojunction optical receiver;

[0075] S4: The decoding module is responsible for converting electrical signals into digital signals and displaying them through the digital tube on the microcontroller development board.

[0076] Application testing:

[0077] In order to verify the sensitivity and stability of the GaN / CuI heterojunction self-powered ultraviolet photodetector prepared by the present invention as an optical signal receiver, in a room lighting environment, the ultraviolet light source is turned on and off according to the binary ASCII code "1" corresponding to the text message "GOOD", and the light response current under 0 bias is obtained by Keysight B1505A power device analyzer. Figure 5 shown.

[0078] It can be seen that the photocurrent reaches 23.6nA when the light source is turned on, and the current drops to about 10pA when the light source is turned off, indicating that the GaN / CuI heterojunction self-powered ultraviolet photodetector prepared by the present invention has excellent sensitivity and stability.

[0079] Example 3

[0080] The difference between this embodiment and embodiment 1 is that the concentration of the CuI precursor solution in step 2) is adjusted to 20 mg / ml, and the remaining steps and processes are all referred to embodiment 1 to obtain the GaN / CuI heterojunction ultraviolet photodetector of this embodiment.

[0081] The performance test is carried out and the results are as follows Figure 6 As shown, the GaN / CuI heterojunction photodetector prepared using 20 mg / ml CuI solution has a good performance under zero bias and 5 μw / cm 2 Under 365nm light, the responsivity and detectivity are 89mA / W and 2.5×10 13 Jones

[0082] Example 4

[0083] The difference between this embodiment and embodiment 1 is that the concentration of the CuI precursor solution in step 2) is adjusted to 60 mg / ml, and the remaining steps and processes are all referred to embodiment 1 to obtain the GaN / CuI heterojunction ultraviolet photodetector of this embodiment.

[0084] The performance test is carried out and the results are as follows Figure 7 As shown, the GaN / CuI heterojunction photodetector prepared using 60mg / ml CuI solution has a good performance under zero bias and 5μw / cm 2 Under 365nm light, the responsivity and detectivity are 187mA / W and 3.5×10 13 Jones.

[0085] Comparative Example 1

[0086] The difference between this embodiment and embodiment 1 is that the concentration of the CuI precursor solution in step 2) is adjusted to 70 mg / ml, resulting in supersaturation.

[0087] It can be seen from comparative examples 1, 3, and 4 that the concentration of the CuI precursor solution has a significant effect on the detection performance. When the solution concentration is too high, the interface quality is poor due to deposition, which affects the transport of carriers. At low solution concentrations, the carrier concentration is insufficient, resulting in insufficient decrease in carrier transport capacity, which in turn leads to a decrease in the performance of the heterojunction.

[0088] Comparative Example 2

[0089] Cited literature [A broadband self-powered UV photodetector of aβ-Ga2O3 / γ-CuIp-n junction];

[0090] In this comparative example, the β-Ga2O3 / CuI heterojunction photodetector is used as a comparative example. Its power supply response and detection rate under zero bias are 0.9 mA / W and 0.65×10 11 Jones.

[0091] Comparative Example 3

[0092] Cited literature [Ultrafast response self-powered UV photodetectors based on GaS / GaN heterojunctions];

[0093] The GaS / GaN heterojunction photodetector is used as a comparative example. Its power supply response and detection rate under zero bias are 6.26 mA / W and 0.65×10 9 Jones.

[0094] By comparing the performance of the heterojunction photodetector of Example 1 with that of Comparative Examples 1 and 2, it can be seen that the performance indicators of the photodetector obtained by adjusting the composite type of the heterojunction are much lower than those of the present application, indicating that the GaN / CuI heterojunction photodetector can generate a larger self-powered photocurrent thanks to the excellent carrier transport properties and suitable energy band structure after the composite of GaN and CuI, and the two work synergistically.

[0095] In summary, the present invention uses a high-performance GaN / CuI heterojunction self-powered photodetector as an optical signal receiver, and forms a typical type II heterojunction based on the combination of GaN and CuI, which exhibits an obvious photovoltaic effect, can achieve a wide spectral response in the UVA and UVC bands, and has very excellent photoelectric performance.

[0096] GaN / CuI heterojunction UV photodetectors are used as optical signal receivers in UV communication systems. Since GaN / CuI heterojunction UV photodetectors can identify UVA and UVC dual-band UV light signals, the system provides a powerful solution for current and future data transmission with its low power consumption, high transmission rate, wide spectrum response, and strong security.

[0097] Since ultraviolet light attenuates faster than visible light and infrared light when propagating in the atmosphere, it is more difficult to be intercepted or interfered with. Therefore, the ultraviolet communication system based on GaN / CuI heterojunction ultraviolet photodetector provides higher security and privacy protection for data transmission, which is very suitable for communication environments that require confidentiality. It can achieve low power consumption of ultraviolet communication system, which is in line with the current "dual carbon" development strategy.

[0098] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A self-powered ultraviolet photodetector based on GaN / CuI heterojunction, characterized in that: The structure of the self-powered ultraviolet photodetector from bottom to top includes: A sapphire substrate layer (100); An n-type GaN thin film layer (200), and a first electrode (400) in ohmic contact with the n-type GaN thin film layer (200); A p-type CuI thin film layer (300), and a second electrode (500) in ohmic contact with the p-type CuI thin film layer (300).

2. The method for preparing a self-powered ultraviolet photodetector based on a GaN / CuI heterojunction according to claim 1, characterized in that: The thickness of the n-type GaN thin film layer (200) is 100 nm to 10 μm, and the thickness of the p-type CuI thin film layer (300) is 10 to 500 nm.

3. The method for preparing a self-powered ultraviolet photodetector based on a GaN / CuI heterojunction according to claim 1, characterized in that: The first electrode (400) and the second electrode (500) are both metal electrodes, including one or more of aluminum, copper, silver, platinum, titanium, indium, and gold.

4. The method for preparing a self-powered ultraviolet photodetector based on a GaN / CuI heterojunction according to any one of claims 1 to 3, characterized in that: include, Preparing a GaN thin film on a sapphire substrate layer (100) by an organic chemical vapor deposition method to form an n-type GaN thin film layer (200); Spin coating a layer of CuI precursor solution on the semi-covered GaN film by spin coating, heating it on a heating stage to form a p-type CuI thin film layer (300), thereby obtaining a GaN / CuI heterojunction; Metal circles are prepared on the surfaces of the n-type GaN thin film layer (200) and the p-type CuI thin film layer (300) respectively to form a first electrode (400) and a second electrode (500), thereby obtaining a GaN / CuI heterojunction ultraviolet photodetector.

5. The method for preparing a self-powered ultraviolet photodetector based on a GaN / CuI heterojunction according to claim 4, characterized in that: In the organic chemical vapor deposition method, the gallium source is trimethylgallium, the nitrogen source is ammonia, the carrier gas is nitrogen, and the nitrogen flow rate is 250-350 sccm.

6. The method for preparing a self-powered ultraviolet photodetector based on a GaN / CuI heterojunction according to claim 4, characterized in that: The concentration of the CuI precursor solution is 20-60 mg / ml, wherein the solute is CuI powder and the solvent is a mixed solution of chlorobenzene and dipropyl sulfide in a volume ratio of 18-20:

1.

7. The method for preparing a self-powered ultraviolet photodetector based on a GaN / CuI heterojunction according to claim 4, characterized in that: The heating time of the heating on the hot stage is 8 to 12 minutes, and the heating temperature is 90 to 110°C.

8. A low power consumption ultraviolet light communication system, characterized in that: include, Ultraviolet light source, emitting ultraviolet light in the range of 200 to 400 nm; An optical signal receiver, using the self-powered ultraviolet photodetector described in claim 1; The data acquisition module consists of a power supply, an amplifier circuit, and a high-precision ammeter; The decoding module consists of an analog-to-digital converter and a microcontroller development board.

9. The low power consumption ultraviolet light communication system as claimed in claim 8, characterized in that: The data acquisition module, wherein: The power supply is a high-precision AC-DC linear power supply that can convert 220V to ±5V with a ripple of less than 1mV; The amplifier circuit is a differential amplifier circuit, which is used to reasonably amplify the electrical signal for subsequent processing; The high-precision ammeter has a measurement range of 0 to 3A and a resolution of 0.1μA; The decoding module, wherein the analog-to-digital converter is used to convert the current signal into a discrete digital signal; and the single-chip microcomputer development board with the relevant program burned in it is used to display the digital signal.

10. The low power consumption ultraviolet light communication system according to any one of claims 7 or 8, characterized in that: The working steps of the low power consumption ultraviolet light communication system include: The ultraviolet light source modulates the light signal with the on-off state of light, generating a light signal wave with coded information, where on is the "1" state and off is the "0" state; The GaN / CuI heterojunction self-powered UV photodetector acts as an optical signal receiver, detecting the transmitted optical signal wave with coded information and converting it into an electrical signal of the same frequency; Among them, the GaN / CuI heterojunction optical signal receiver can achieve self-powered operation under zero volt bias; The data acquisition module amplifies and reads the electrical signal converted by the GaN / CuI heterojunction optical receiver; The decoding module is responsible for converting electrical signals into digital signals and displaying them through the digital tubes on the microcontroller development board.

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