Heterojunction self-driven broadband array photoelectric detector and preparation method thereof

Abstract

The invention discloses a heterojunction self-driven broadband array photoelectric detector and a preparation method thereof. The photoelectric detector comprises a substrate, an Au electrode is arranged on one side of the substrate, p-Te films are distributed on the surface of the substrate in an array mode, the p-Te films are connected with the Au film electrode, and the Au film electrode is arranged on a conducting layer. The preparation method comprises the following steps: evaporating an Au electrode at one end of a substrate; placing a mask plate on the surface of the obtained object, placing the object in a second temperature zone of a vacuum tube furnace, placing Te powder in a first temperature zone of the vacuum tube furnace, growing a p-Te film on the surface of the substrate, and removing the mask plate to obtain a p-n type heterojunction material; and covering the p-n type heterojunction material with the conductive surface of the conductive layer on which the Au film electrode is evaporated. According to the invention, the large-area Te film is synthesized, and the heterojunction type self-powered broadband array photoelectric detector of the integrated two-dimensional single crystal tellurium film with the resolution ratio of 64 pixels is prepared on the substrate in situ for the first time.

Description

Technical Field

[0001] The present invention relates to a photoelectric detector and a manufacturing method thereof, and in particular to a heterojunction self-driven wide-band array photoelectric detector and a manufacturing method thereof. Background Art

[0002] Photodetectors convert light into electrical signals and are the core of information acquisition. Photodetectors operating at different wavelengths have potential application prospects in military and civilian fields such as chemical / biological analysis, encrypted communications, optoelectronic devices, and imaging. Imaging is an important application field of photodetectors. Multispectral image fusion technology aims to extract the most critical information from images of multiple wavelengths and integrate it into a comprehensive image, thereby enhancing the richness of data and the value of subsequent applications (such as machine vision, autonomous driving, medical analysis, etc.). With the leapfrog progress of photodetection technology, especially the emergence of devices with wider response spectral bands, pixel-level image fusion strategies have become increasingly feasible, enabling the capture of multispectral information through a single detector.

[0003] However, the existing multispectral imaging technology generally acquires a multispectral image by switching filters of different wavelengths to obtain a corresponding spectral image in sequence; or uses a variety of different detectors to image the target object separately to obtain a multispectral image. Both acquisition methods are time-sharing acquisition, and the movement of the target object or the detector will affect the imaging accuracy. Specifically, how to use a single device to achieve pixel-level multispectral image fusion (PLMSIF) technology across deep ultraviolet (UVC), visible light (Vis) and near infrared (NIR) spectra has shown great application potential and market demand in various fields such as medical image analysis and security.

[0004] The two-dimensional van der Waals (vdW) semiconductor materials, which do not contain dangling bonds on their surfaces and have excellent electrical properties, provide a flexible platform for building ultra-compact, high-performance optoelectronic devices with a wide spectrum, making them promising for advanced monolithic integrated circuits. Compared with traditional photoconductive detectors, pn junction photodetectors based on the photovoltaic effect offer good potential for miniaturized integrated application devices due to their high energy conversion rate, small structural size, and high charge separation efficiency.

[0005] However, it is difficult to develop high-mobility and high-stability p-type semiconductors in the prior art, which hinders the further development of high-performance multifunctional integrated circuits. In recent years, researchers have been committed to exploring high-mobility p-type semiconductors, including metal oxides, chalcogenides, low-dimensional nanomaterials, etc. However, these materials are further limited in their application due to high manufacturing costs (such as In and Ga), harmful environmental pollution (such as Cd and Pb), and their own instability in the environment and difficulty in large-scale preparation. The Chinese patent with publication number CN111850556A discloses a room-temperature wide-spectrum photodetector based on a two-dimensional cobalt selenide film and a preparation method. For the first time, a wide spectral response band of 450 nanometers to 10.6 microns laser was achieved at room temperature. The response rate is high but it cannot be used in the ultraviolet spectrum region. A Chinese patent with publication number CN117238978A discloses a self-driven wide-spectrum photodetector and a method for preparing the same. Although the Schottky-type self-driven photodetector composed of narrow-bandgap two-dimensional materials mentioned above achieves a wide detection spectrum range from visible light to infrared spectrum and high optical detection performance, it is still manufactured using a difficult transfer method and is still a long way from successfully manufacturing a device array. Summary of the invention

[0006] Purpose of the invention: In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a heterojunction self-driven wide-band array photodetector with a resolution of 64 pixels and good detection performance. Another purpose of the present invention is to provide a method for preparing a large-area Te thin film, which is simple and convenient for preparing a heterojunction self-driven wide-band array photodetector.

[0007] Technical solution: The heterojunction self-driven wide-band array photodetector described in the present invention includes a substrate, an Au electrode is arranged on one side of the substrate, a p-Te film is distributed in an array on the surface of the substrate, the p-Te film is connected to the Au thin film electrode, and the Au thin film electrode is arranged on a conductive layer.

[0008] Furthermore, the thickness of the n-type semiconductor base substrate is 0.1 to 0.35 mm and the carrier concentration is 10 16～ 10 18 cm -3 ; The substrate is any one of n-GaAs, n-GaN, n-AlGaN, n-ZnO, and n-SiC.

[0009] Furthermore, the thickness of the Au electrode is 40-60 nm.

[0010] Furthermore, the conductive layer is ITO conductive glass or FTO conductive glass.

[0011] Furthermore, the thickness of the p-Te film is 1.0-3.0 μm, and the resistivity is 1.57×10 -3~2.54×10 -3 Ω·m.

[0012] Furthermore, the response band of the heterojunction self-driven wide-band array photodetector is 254-1050 nm.

[0013] The method for preparing a heterojunction self-driven wide-band array photodetector according to the present invention comprises the following steps:

[0014] Step 1, evaporating an Au electrode at one end of the substrate;

[0015] Step 2: placing a mask plate on the surface of the product obtained in step 1, placing the product in the second temperature zone of a vacuum tube furnace, placing Te powder in the first temperature zone of the vacuum tube furnace, growing a p-Te film on the surface of the substrate, removing the mask plate, and obtaining a pn-type heterojunction material;

[0016] Step three, covering the conductive side of the conductive layer with the Au thin film electrode evaporated on the pn-type heterojunction material to obtain a heterojunction self-driven wide-band array photodetector.

[0017] Furthermore, in step 1, the substrate is placed in acetone, ethanol and deionized water in sequence for ultrasonic cleaning.

[0018] Furthermore, in step 2, the purity of Te powder is ≥99.0%. The first temperature zone is raised to 400-500°C within 20-40 minutes, the second temperature zone is raised to 300-400°C within 20-40 minutes, the distance between the first temperature zone and the second temperature zone is set to 16-20 cm, and the temperature is kept for 50-80 minutes after heating.

[0019] Preparation principle: The melting point of tellurium at standard atmospheric pressure is set at 449.15°C. The steps of preparing single crystals by sublimation and condensation mechanism involve converting Te raw materials into gaseous sublimates in the high temperature area, and then condensing and solidifying these gaseous substances into single crystals in the low temperature area. Physical vapor deposition technology can achieve the synthesis of high-quality Te thin films by precisely controlling key factors such as source temperature, substrate temperature, deposition time and gas pressure. In view of the fact that the melting point is restricted by the material form and gas pressure conditions, we selected tellurium powder as the starting material for growth and placed it in a sealed quartz tube. By implementing high vacuum extraction to reduce the gas pressure during the growth process, it is expected that the required growth temperature can be effectively reduced.

[0020] Beneficial effects: Compared with the prior art, the present invention has the following significant features:

[0021] 1. A simple strategy for growing p-Te thin film arrays by one-step physical vapor deposition was developed, which provides a general method for the synthesis of large-area Te thin films. For the first time, an integrated two-dimensional single-crystal tellurium thin film heterojunction self-powered broadband array photodetector with a resolution of 64 pixels was in situ prepared on an n-type semiconductor substrate;

[0022] 2. The present invention benefits from the excellent contact characteristics between Weyl semiconductor Te and substrate and the favorable band arrangement between interfaces. The unit n-GaAs / p-Te device exhibits excellent light detection performance under solar-blind ultraviolet-near infrared wide-band illumination, including a maximum responsivity of 55mA / W and a detection rate of 2×10 12 Jones, switch ratio 10 5 As well as millisecond-level response speed (2.6ms / 5.1ms), the response speed and detection rate of a single-pixel heterojunction device are two orders of magnitude higher than those of a device without Te film loading;

[0023] 3. Taking advantage of the excellent anisotropic properties of Te film, the device has an anisotropic photocurrent ratio of 1.72 under 1050nm light, and has significant polarization-sensitive light detection capabilities;

[0024] 4. By using photodetector arrays, high-contrast imaging functions and ultra-sensitive multi-pixel image fusion functions have been successfully realized, which promotes the development of integrated optoelectronic devices and provides new ideas for realizing ultra-wideband light detection with high detection performance and multi-functional applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic diagram of the structure of the product obtained by S1 of the present invention;

[0026] Figure 2 It is a schematic diagram of the structure of the product obtained by S2 of the present invention;

[0027] Figure 3 It is a schematic diagram of the structure of the product obtained by S3 of the present invention;

[0028] Figure 4 It is a schematic diagram of the structure of the product obtained by S4 of the present invention;

[0029] Figure 5 It is a schematic diagram of the structure of the present invention;

[0030] Figure 6 It is a physical diagram of the present invention;

[0031] Figure 7 are Raman spectra of n-GaAs, p-Te and n-GaAs / p-Te of the present invention;

[0032] Figure 8 is a photoelectric performance characterization diagram of the present invention;

[0033] Fig. 9 is a photocurrent and responsivity graph of the present invention;

[0034] Fig.10 is the light on / off ratio and D of the present invention when the light intensity is different * ;

[0035] Fig.11 is the polarization angle-dependent It curve of the present invention;

[0036] Fig.12 is a polar coordinate diagram of the photocurrent of the present invention relative to the polarization angle of the incident light of 1050 nm;

[0037] Fig.13 This is a graph of the test results of pixel-level multispectral image fusion in the field of medical imaging according to the present invention. DETAILED DESCRIPTION

[0038] In the following examples, the purity of the high-purity Te powder is ≥99.0%.

[0039] Example 1

[0040] A method for preparing a heterojunction self-driven wide-band array photodetector comprises the following steps:

[0041] S1, such as Figure 1 As shown, the thickness is 0.35 mm and the carrier concentration is 2.3×10 18 cm -3 The n-GaAs substrate 1 is placed in acetone, ethanol and deionized water in turn, cleaned with an ultrasonic cleaner for 15 minutes, then the surface moisture is purged with nitrogen, and finally an Au electrode 2 with a thickness of 40 nm is evaporated on one end of the n-GaAs substrate 1 using an electron beam evaporator for standby use.

[0042] S2, such as Figure 2 As shown, 100 mg of Te powder is placed in the first temperature zone as a growth source, and a customized mask plate 6 is placed on the n-GaAs substrate 1 with the Au electrode 2 evaporated, and placed in the second temperature zone of the vacuum tube furnace, 18 cm away from the first temperature zone. Before the reaction, an oxygen-free environment is provided to the sealed quartz tube. After vacuuming, argon gas is injected into the tube, and the quartz tube is cleaned for 10 minutes, the air is removed, and then high-purity argon gas is filled into the tube to repeat the rinsing several times. During the synthesis process, the first temperature zone is raised to 445°C within 30 minutes, and the second temperature zone is raised to 345°C within 25 minutes. The two temperature zones are kept warm for 60 minutes each.

[0043] S3, such as Figure 3 Then, the film is cooled to room temperature in an argon atmosphere at 20 sccm, and the mask plate 6 is removed to obtain an n-GaAs / p-Te array device.

[0044] S4, such as Figure 4 , take the ITO conductive glass (conductive layer 5) and place it in acetone, ethanol and deionized water in turn, use an ultrasonic cleaner to clean it for 15 minutes, then use nitrogen to blow away the surface moisture, and finally use an electron beam evaporator to evaporate a 40nm thick Au thin film electrode 4 on one end of the conductive surface of the ITO conductive glass for use.

[0045] S5. Cover the conductive side of the ITO conductive glass (conductive layer 5) with the Au thin film electrode 4 evaporated on the n-GaAs / p-Te array device, and clamp the entire device with two metal clips to obtain a heterojunction self-driven wide-band array photodetector.

[0046] like Figure 5 The left upper surface of the n-GaAs substrate 1 of the heterojunction self-driven wide-band array photodetector obtained in this embodiment has an Au electrode 2 with a thickness of 40 nm, and an array-distributed p-Te film 3 on the surface. The p-Te film 3 is connected to the Au film electrode 4 one by one, and the Au film electrode 4 is arranged on the conductive layer 5. The thickness of the p-Te film 3 is 2.5 μm, and the resistivity is 4.36×10 -3 Ω·m.

[0047] like Figure 6 The macroscopic side length of the heterojunction self-driven wide-band array photodetector is 1 cm.

[0048] The photoelectric performance of the heterojunction self-driven wide-band array photodetector obtained in this embodiment was tested under the following test conditions: the photoelectric performance was measured at room temperature 25°C using a Keysight B1500A semiconductor analyzer. The results showed that under 1050nm illumination, the responsivity was 55mA / W and the on / off ratio was 2.1×10 5 , the specific detection rate is 2×10 12 , the photocurrent anisotropy ratio is 1.72.

[0049] like Figure 7 , depicting the Raman spectra of Te, GaAs, and GaAs / Te heterojunction, respectively. Peaks of Te and GaAs can be observed in the Raman spectrum of the GaAs / Te interface, indicating the successful formation of the GaAs / Te heterojunction. In addition, the Te film has peaks at 92, 120, and 141 cm -1 Three main Raman activity modes appear at the surface, which are attributed to E1, A1 and E2, among which the narrow A1 peak also indicates the high crystalline quality of the Te film.

[0050] like Figure 8, showing the It curve of the unit GaAs / Te heterojunction device under 0V bias and the same optical power wavelength 254~1050nm irradiation. The device shows the highest photoresponse at a wavelength of 1050nm.

[0051] like Fig. 9 , the photocurrent (I ph ) as a function of the incident light intensity (P) is fitted to Iph∝P θ , the power index (θ) of the GaAs / Te heterojunction device is 0.97. The θ value of GaAs / Te is close to 1, which again shows that the high-quality vdW interface has almost no carrier traps. In addition, the maximum R of the GaAs / Te heterojunction device is 55mA / W.

[0052] like Fig.10 , describes the light on / off ratio and specific detectivity (D) of GaAs / Te devices at different powers when self-powered * ) changes. The maximum D * The value is 2×10 12 Jones, maximum on / off ratio is 10 5 .

[0053] like Fig.11 , describes that under 1050nm illumination, by rotating the polarizer to modulate the polarization direction of light, the photocurrent of the GaAs / Te heterojunction device exhibits stable periodic changes.

[0054] like Fig.12 , describing that the polarization photocurrent of GaAs / Te heterojunction device at different polarization angles shows significant periodic variation with the change of polarization angle in polar coordinates, and the maximum dichroic ratio (I max / I min ) is 1.72.

[0055] like Fig.13 , using GaAs / Te array detectors and combining pixel-level multispectral image fusion technology of deep ultraviolet (UVC), visible light (Vis) and near-infrared (NIR) spectra, is expected to be used for accurate evaluation of medical images.

[0056] Application Example 1

[0057] The single crystal tellurium thin film heterojunction self-driven wide-band array photodetector prepared in Example 1 was subjected to a pixel-level multi-spectral image fusion test in the field of medical imaging.

[0058] The test conditions are: using Keysight B1500A semiconductor analyzer to measure its photoelectric properties at room temperature 25℃.

[0059] The hand imaging under 254nm, 520nm and 1050nm illumination respectively reveals the clear edges and details of the "hand", producing the best fusion image of UVC, Vis and NIR. The test results are as follows Fig.13 As shown. The self-driven wide-band array photodetector based on single crystal tellurium thin film heterojunction prepared in the above Example 1 can be applied to the field of medical imaging. UVC images focus on the visualization of inflammation reduction and wound healing process, visible light images are helpful for appearance evaluation, and near-infrared images deeply reveal the fine structure of biological tissues. The images of these three spectral ranges are seamlessly merged into a single image through advanced visual algorithms, which can efficiently and comprehensively map the detailed patterns required for medical diagnosis, and provide more comprehensive and accurate information support for medical decision-making.

[0060] Example 2

[0061] A method for preparing a heterojunction self-driven wide-band array photodetector comprises the following steps:

[0062] S1, thickness is 0.25 mm, carrier concentration is 2.3×10 16 cm -3 The n-ZnO substrate 1 is placed in acetone, ethanol and deionized water in turn, cleaned with an ultrasonic cleaner for 15 minutes, then the surface moisture is purged with nitrogen, and finally an Au electrode 2 with a thickness of 40 nm is evaporated on one end of the n-ZnO substrate using an electron beam evaporator for standby use.

[0063] S2. Place 100 mg of Te powder in the first temperature zone as a growth source, place the customized mask plate 6 on the n-ZnO substrate 1 with the Au electrode 2 evaporated, and place it in the second temperature zone of the vacuum tube furnace, 18 cm away from the first temperature zone. Before the reaction, provide an oxygen-free environment for the sealed quartz tube. After evacuation, inject argon into the tube, clean the quartz tube for 10 minutes, exclude air, and then fill the tube with high-purity argon and rinse it several times. During the synthesis process, the first temperature zone is raised to 445°C within 30 minutes, and the second temperature zone is raised to 345°C within 25 minutes. The two temperature zones are kept warm for 60 minutes each.

[0064] S3, then cool to room temperature in an argon atmosphere at 20 sccm, remove the mask 6, and obtain an n-ZnO / p-Te array device. The thickness of the p-Te film 3 is 2.0 μm, and the resistivity is 2.16×10 -3 Ω·m.

[0065] S4. Take the ITO conductive glass (conductive layer 5) and place it in acetone, ethanol and deionized water in turn, use an ultrasonic cleaner to clean it for 15 minutes, then use nitrogen to blow away the surface moisture, and finally use an electron beam evaporator to evaporate a 40nm thick Au thin film electrode 4 on one end of the conductive surface of the ITO conductive glass for use.

[0066] S5. Cover the conductive side of the ITO conductive glass (conductive layer 5) with the Au thin film electrode 4 evaporated on the n-ZnO / p-Te array device, and clamp the entire device with two metal clips to obtain a heterojunction self-driven wide-band array photodetector.

[0067] The heterojunction self-driven broadband array photodetector obtained in this example has a responsivity of 31 mA / W and an on / off ratio of 1.3×10 3 , the specific detection rate is 7.3×10 9 , the photocurrent anisotropy ratio is 1.21.

[0068] Example 3

[0069] A method for preparing a heterojunction self-driven wide-band array photodetector comprises the following steps:

[0070] S1, thickness is 0.25 mm, carrier concentration is 4.51×10 18 cm -3 The n-GaN substrate 1 is placed in acetone, ethanol and deionized water in turn, cleaned for 15 minutes using an ultrasonic cleaner, then the surface moisture is purged using nitrogen, and finally a 40nm thick Au electrode 2 is evaporated on one end of the n-GaN substrate using an electron beam evaporator for standby use.

[0071] S2. Place 100 mg of Te powder in the first temperature zone as a growth source, place the customized mask plate on the n-GaN substrate 1 with the Au electrode 2 evaporated, and place it in the second temperature zone of the vacuum tube furnace, 18 cm away from the first temperature zone. Before the reaction, provide an oxygen-free environment for the sealed quartz tube. After evacuation, inject argon into the tube, clean the quartz tube for 10 minutes, exclude the air, and then fill the tube with high-purity argon and rinse it several times. During the synthesis process, the first temperature zone rises to 445°C within 30 minutes, and the second temperature zone rises to 345°C within 25 minutes. The two temperature zones are kept warm for 60 minutes each.

[0072] S3, then cool to room temperature in an argon atmosphere at 20 sccm, remove the mask 6, and obtain an n-GaN / p-Te array device. The thickness of the p-Te film 3 is 2.1 μm, and the resistivity is 1.64×10 -3 Ω·mΩ·cm.

[0073] S4. Take the ITO conductive glass (conductive layer 5) and place it in acetone, ethanol and deionized water in turn, use an ultrasonic cleaner to clean it for 15 minutes, then use nitrogen to blow away the surface moisture, and finally use an electron beam evaporator to evaporate a 40nm thick Au thin film electrode 4 on one end of the conductive surface of the ITO conductive glass for use.

[0074] S5. Cover the conductive side of the ITO conductive glass (conductive layer 5) with the Au thin film electrode 4 evaporated on the n-GaN / p-Te array device, and clamp the entire device with two metal clips to obtain a heterojunction self-driven wide-band array photodetector.

[0075] The heterojunction self-driven broadband array photodetector obtained in this example has a responsivity of 43 mA / W and an on / off ratio of 1.4×10 3 , the specific detection rate is 4.1×10 10 , the photocurrent anisotropy ratio is 1.51.

[0076] Example 4

[0077] A method for preparing a heterojunction self-driven wide-band array photodetector comprises the following steps:

[0078] S1, thickness is 0.1 mm, carrier concentration is 3.3×10 16 cm -3 The n-AlGaN substrate 1 is placed in acetone, ethanol and deionized water in turn, cleaned with an ultrasonic cleaner for 15 minutes, then the surface moisture is purged with nitrogen, and finally an Au electrode 2 with a thickness of 50 nm is evaporated on one end of the n-AlGaN substrate 1 using an electron beam evaporator for standby use.

[0079] S2. Place 100 mg of Te powder in the first temperature zone as a growth source, place the customized mask plate 6 on the n-AlGaN substrate 1 with the Au electrode 2 evaporated, and place it in the second temperature zone of the vacuum tube furnace, 16 cm away from the first temperature zone. Before the reaction, provide an oxygen-free environment for the sealed quartz tube. After evacuation, inject argon into the tube, clean the quartz tube for 10 minutes, exclude the air, and then fill the tube with high-purity argon and rinse it several times. During the synthesis process, the first temperature zone is raised to 400°C within 20 minutes, and the second temperature zone is raised to 300°C within 20 minutes. The two temperature zones are kept warm for 50 minutes each.

[0080] S3, then cool to room temperature in an argon atmosphere at 20 sccm, remove the mask 6, and obtain an n-AlGaN / p-Te array device. The thickness of the p-Te film 3 is 1.0 μm, and the resistivity is 2.54×10 -3 Ω·m.

[0081] S4. Take the ITO conductive glass (conductive layer 5) and place it in acetone, ethanol and deionized water in turn, use an ultrasonic cleaner to clean it for 15 minutes, then use nitrogen to blow away the surface moisture, and finally use an electron beam evaporator to evaporate a 50nm thick Au thin film electrode 4 on one end of the conductive surface of the ITO conductive glass for use.

[0082] S5. Cover the conductive side of the ITO conductive glass (conductive layer 5) with the Au thin film electrode 4 evaporated on the n-AlGaN / p-Te array device, and clamp the entire device with two metal clips to obtain a heterojunction self-driven wide-band array photodetector.

[0083] The heterojunction self-driven broadband array photodetector obtained in this example has a responsivity of 21 mA / W and an on / off ratio of 3.3×10 3 , the specific detection rate is 4.2×10 10 , the photocurrent anisotropy ratio is 1.243.

[0084] Example 5

[0085] A method for preparing a heterojunction self-driven wide-band array photodetector comprises the following steps:

[0086] S1, thickness is 1.5 mm, carrier concentration is 4.56×10 18 cm -3 The n-SiC substrate 1 is placed in acetone, ethanol and deionized water in turn, cleaned for 15 minutes using an ultrasonic cleaner, then the surface moisture is purged using nitrogen, and finally an Au electrode 2 with a thickness of 60 nm is evaporated on one end of the n-SiC substrate using an electron beam evaporator for standby use.

[0087] S2. Place 100 mg of Te powder in the first temperature zone as a growth source, place the customized mask plate 6 on the n-SiC substrate 1 with the Au electrode 2 evaporated, and place it in the second temperature zone of the vacuum tube furnace, 20 cm away from the first temperature zone. Before the reaction, provide an oxygen-free environment for the sealed quartz tube. After evacuation, inject argon into the tube, clean the quartz tube for 10 minutes, exclude the air, and then fill the tube with high-purity argon and rinse it several times. During the synthesis process, the first temperature zone is raised to 500°C within 40 minutes, and the second temperature zone is raised to 400°C within 40 minutes. The two temperature zones are kept warm for 80 minutes each.

[0088] S3, then cool to room temperature in an argon atmosphere at 20 sccm, remove the mask 6, and obtain an n-SiC / p-Te array device. The thickness of the p-Te film 3 is 3.0 μm, and the resistivity is 1.57×10 -3 Ω·m.

[0089] S4. Take the FTO conductive glass (conductive layer 5) and place it in acetone, ethanol and deionized water in turn, use an ultrasonic cleaner to clean it for 15 minutes, then use nitrogen to blow away the surface moisture, and finally use an electron beam evaporator to evaporate a 60nm thick Au thin film electrode 4 on one end of the conductive surface of the FTO conductive glass for use.

[0090] S5. Cover the conductive side of the FTO conductive glass (conductive layer 5) with the Au thin film electrode 4 evaporated on the n-ZnO / p-Te array device, and clamp the entire device with two metal clips to obtain a heterojunction self-driven wide-band array photodetector.

[0091] The heterojunction self-driven broadband array photodetector obtained in this example has a responsivity of 17 mA / W and an on / off ratio of 2.3×10 2 , the specific detection rate is 2.4×10 9 , the photocurrent anisotropy ratio is 1.11.

[0092] Comparative Example 1

[0093] The remaining steps of this comparative example are the same as those of Example 1, except that the Te powder is replaced with a Te / Se mixed powder with a ratio of 7:3. It is found that these pre-mixed Se / Te vapor mixtures grow into large / thick crystals on n-GaAs substrates through vdW epitaxy. x Te 1-x Alloy two-dimensional nanosheets are difficult to form large-area dense films.

[0094] The photoelectric performance of the heterojunction self-driven wide-band array photodetector obtained in this embodiment was tested under the following test conditions: the photoelectric performance was measured at room temperature 25°C using a Keysight B1500A semiconductor analyzer. The results showed that under 1050nm illumination, the responsivity was 8mA / W and the on / off ratio was 4.4×10 2 , the specific detection rate is 1.3×10 10 , the photocurrent anisotropy ratio is 1.03.

[0095] Comparative Example 2

[0096] The remaining steps of this comparative example are the same as those of Example 1, except that the synthesis process conditions in step S2 are replaced by the first temperature zone being raised to 550°C within 15 minutes, the second temperature zone being raised to 450°C within 15 minutes, and the two temperature zones being kept warm for 40 minutes each. The results show that the excessively high growth temperature of the first temperature zone leads to an excessively fast vaporization rate of the precursor, making it difficult for the product to reach an ideal crystalline state during the deposition process, resulting in a decrease in the crystallinity of the Te film, an uneven grain size, and even the generation of an amorphous structure.

[0097] The photoelectric performance of the heterojunction self-driven wide-band array photodetector obtained in this embodiment was tested under the following test conditions: the photoelectric performance was measured at room temperature 25°C using a Keysight B1500A semiconductor analyzer. The results showed that under 1050nm illumination, the responsivity was 0.7mA / W and the on / off ratio was 1.5×10 2, the specific detection rate is 2.6×10 8 , the photocurrent anisotropy ratio is 1.13.

[0098] Comparative Example 3

[0099] The remaining steps of this comparative example are the same as those of Example 1, except that the synthesis process conditions in step S2 are replaced by the first temperature zone being raised to 380°C within 45 minutes, the second temperature zone being raised to 280°C within 45 minutes, and the two temperature zones being kept warm for 90 minutes each. The results show that if the growth temperature in the first temperature zone is too low, the vaporization rate of the precursor will be slowed down, resulting in a decrease in the deposition rate, thereby affecting the uniformity and density of the Te film. In addition, too low a temperature may also cause the precursor to fail to fully decompose or react, resulting in unreacted raw materials remaining in the product.

[0100] Table 1 Photoelectric performance of photodetectors obtained in Examples 1 to 5 and Comparative Examples 1 to 3

[0101] Responsivity (mA / W) On / off ratio Specific Detection Rate (Jones) Photocurrent anisotropy ratio Example 1 55 <![CDATA[2.1×10 5 ]]> <![CDATA[2×10 12 ]]> 1.72 Example 2 31 <![CDATA[1.3×10 3 ]]> <![CDATA[7.3×10 9 ]]> 1.21 Example 3 43 <![CDATA[1.4×10 3 ]]> <![CDATA[4×10 10 ]]> 1.51 Example 4 21 <![CDATA[3.3×10 3 ]]> <![CDATA[4.2×10 10 ]]> 1.24 Example 5 17 <![CDATA[2.3×10 2 ]]> <![CDATA[2.4×10 9 ]]> 1.11 Comparative Example 1 8.0 <![CDATA[4.4×10 2 ]]> <![CDATA[1.3×10 8 ]]> 1.03 Comparative Example 2 0.7 <![CDATA[1.5×10 2 ]]> <![CDATA[2.6×10 8 ]]> 1.13 Comparative Example 3 1.4 <![CDATA[5.5×10 2 ]]> <![CDATA[1.7×10 9 ]]> 1.32

[0102] The photoelectric performance of the heterojunction self-driven wide-band array photodetectors obtained in Examples 1 to 5 and Comparative Examples 1 to 3 was tested. The test conditions were: using a Keysight B1500A semiconductor analyzer at room temperature 25°C to measure their photoelectric performance. The results showed that under 1050nm illumination, the responsivity was 1.4mA / W, the on / off ratio was 5.5×10 2 , the specific detection rate is 1.7×10 9 , the photocurrent anisotropy ratio is 1.32.

[0103] The above photoelectric properties are summarized in Table 1. It can be seen that the self-driven wide-band array photodetector based on single crystal tellurium thin film heterojunction prepared by the present invention has excellent performance. The best embodiment is embodiment 1, whose responsivity reaches 55mA / W and the on-off ratio reaches 10 5 , the specific detection rate reaches 2×10 12 , the photocurrent anisotropy ratio reaches 1.72.

Claims

1. A heterojunction self-driven wide-band array photodetector, characterized in that: The invention comprises a substrate (1), an Au electrode (2) is arranged on one side of the substrate (1), a p-Te film (3) is distributed in an array on the surface of the substrate (1), the p-Te film (3) is connected to an Au film electrode (4), and the Au film electrode (4) is arranged on a conductive layer (5).

2. The heterojunction self-driven wide-band array photodetector according to claim 1, characterized in that: The thickness of the substrate (1) is 0.1 to 0.35 mm, and the carrier concentration is 10 16～ 10 18 cm -3 ; The substrate (1) is any one of n-GaAs, n-GaN, n-AlGaN, n-ZnO, and n-SiC.

3. The heterojunction self-driven wide-band array photodetector according to claim 1, characterized in that: The thickness of the Au electrode (2) is 40-60 nm.

4. The heterojunction self-driven wide-band array photodetector according to claim 1, characterized in that: The conductive layer (5) is ITO conductive glass or FTO conductive glass.

5. The heterojunction self-driven wide-band array photodetector according to claim 1, characterized in that: The p-Te film (3) has a thickness of 1.0 to 3.0 μm and a resistivity of 1.57×10 -3 ~2.54×10 -3 Ω·m.

6. The heterojunction self-driven wide-band array photodetector according to claim 1, characterized in that: The response band of the heterojunction self-driven wide-band array photoelectric detector is 254-1050 nm.

7. A method for preparing the heterojunction self-driven wide-band array photodetector according to claim 1, characterized in that: The following steps are involved: Step 1, evaporating an Au electrode (2) on one end of a substrate (1); Step 2: placing a mask plate (6) on the surface of the product obtained in step 1, placing the product in the second temperature zone of a vacuum tube furnace, placing Te powder in the first temperature zone of the vacuum tube furnace, growing a p-Te film (3) on the surface of the substrate (1), removing the mask plate (6), and obtaining a pn-type heterojunction material; Step three, covering the conductive side of the conductive layer (5) on which the Au thin film electrode (4) is evaporated on the pn-type heterojunction material to obtain a heterojunction self-driven wide-band array photodetector.

8. The method for preparing the heterojunction self-driven wide-band array photodetector according to claim 7, characterized in that: In the step 1, the substrate (1) is placed in acetone, ethanol and deionized water in sequence and ultrasonically cleaned.

9. The method for preparing the heterojunction self-driven wide-band array photodetector according to claim 7, characterized in that: In the step 2, the purity of Te powder is ≥99.0%.

10. The method for preparing the heterojunction self-driven wide-band array photodetector according to claim 7, characterized in that: In the step 2, the first temperature zone is raised to 400-500° C. within 20-40 minutes, and the second temperature zone is raised to 300-400° C. within 20-40 minutes. The distance between the first temperature zone and the second temperature zone is set to 16-20 cm, and the temperatures are kept warm for 50-80 minutes after the temperature is raised.

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