Bipolar response self-powered wide-spectrum photoelectric detector and preparation method thereof

Abstract

The invention provides a bipolar response self-powered wide-spectrum photoelectric detector and a preparation method thereof. The bipolar response self-powered wide-spectrum photoelectric detector comprises a substrate, a buffer layer, an n-type semiconductor layer and a p-type semiconductor layer which are sequentially stacked, a metal electrode is arranged on the surface of one side, far away from the n-type semiconductor layer, of the p-type semiconductor layer; the material of the n-type semiconductor layer comprises ZnO; the p-type semiconductor layer is made of Te doped with rare earth elements. An n-type semiconductor layer comprising ZnO and a p-type semiconductor layer comprising rare earth element doped Te are introduced into the photoelectric detector, a reverse photocurrent is formed by using a photovoltaic effect of a p-n junction, a forward current is generated by a photo-thermal electric effect of a Te film, the photovoltaic effect and the photo-thermal electric effect are integrated in one device, and the photoelectric detector has a good photoelectric detection effect. And finally, the multifunctional bipolar response self-powered wide-spectrum photoelectric detector is obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor, in particular to the field of self-powered photodetector, and especially to a bipolar response self-powered wide-spectrum photodetector and a preparation method thereof. BACKGROUND

[0002] Self-powered photodetectors (PDs) have attracted extensive attention due to their wide applications in communication, imaging, environmental monitoring, etc. At present, the research on self-powered PDs mainly focuses on improving the response rate, response speed, detection rate and making wearable devices. However, with the development of technology, the traditional PDs cannot meet the requirements of some special application scenarios due to their single detection function.

[0003] CN116864567A discloses a preparation method of a self-powered photodetector, the self-powered photodetector and application. The preparation method comprises: spin-coating bismuth iron precursor solution on part of the Ga2O3 thin film surface of a Ga2O3 thin film substrate, and then heat treating to form a BiFeO3 thin film on the part of the Ga2O3 thin film surface. The BiFeO3 thin film and the Ga2O3 thin film form a heterojunction. Point electrodes are prepared on the surface of the Ga2O3 thin film in the remaining area and the surface of the BiFeO3 thin film in the part of the area to obtain the self-powered photodetector. The photodetector prepared by the method has extremely low dark current and good light-to-dark current ratio, fast response speed, stable self-powered operation, and can well meet the requirements of practical applications.

[0004] CN111244207A discloses a wide-band self-powered antimony thin film photodetector composed of an antimony thin film and a silver electrode. The antimony thin film is prepared by gas phase deposition of Sb powder on a substrate. The antimony thin film prepared by gas phase deposition of Sb powder on a substrate and the silver electrode are combined to form the wide-band self-powered antimony thin film photodetector. The antimony thin film has high quality and good continuity, and the manufacturing process is simple. The re-combination process of the antimony thin film and the base material is omitted. The obtained photodetector has self-powered characteristics and wide-band working characteristics. When the substrate is a flexible substrate, the obtained flexible photodetector also has excellent mechanical flexibility.

[0005] CN115842066A discloses a self-powered photoelectric detector and a preparation method thereof. The self-powered photoelectric detector comprises a first electrode, a p-n junction structure and a second electrode arranged in sequence along a first direction, the p-n junction structure comprises at least one p-n junction formed by cooperation of at least one first nanowire and at least one second nanowire, the first nanowire and the second nanowire have different conductive types, and both ends of the first nanowire and the second nanowire are electrically connected with the first electrode and the second electrode respectively. The present application closely connects gallium nitride nanowires and gallium oxide nanowires to form a p-n junction, realizes the effect of detection without external power supply, and each gallium nitride / gallium oxide nanowire under the connection of the metal electrode participates in the work, greatly improving the detection performance.

[0006] Therefore, it is of great significance to provide a multifunctional photoelectric detector capable of realizing wide spectrum detection from the ultraviolet band to the infrared band and capable of realizing change of current polarity under different wavelength illuminations and a preparation method thereof. SUMMARY

[0007] In view of the deficiencies of the prior art, the purpose of the present application is to provide a bipolar response self-powered wide spectrum photoelectric detector and a preparation method thereof. The present application introduces an n-type semiconductor layer including ZnO and a p-type semiconductor layer including rare earth element doped Te into the photoelectric detector, forms a reverse photocurrent by using the photovoltaic effect (PV) of the p-n junction, generates a forward current by the photothermal electric effect (PTE) of the Te film, integrates the photovoltaic effect and the photothermal electric effect in one device, and finally obtains a multifunctional bipolar response self-powered wide spectrum photoelectric detector.

[0008] To achieve the purpose of the present application, the present application adopts the following technical solutions:

[0009] In a first aspect, the present application provides a bipolar response self-powered wide spectrum photoelectric detector, which comprises a substrate, a buffer layer, an n-type semiconductor layer and a p-type semiconductor layer arranged in sequence. The p-type semiconductor layer is provided with a metal electrode on the side surface away from the n-type semiconductor layer. The material of the n-type semiconductor layer comprises ZnO. The material of the p-type semiconductor layer comprises rare earth element doped Te.

[0010] The "wide spectrum" of the present application refers to different wavelength intervals from the ultraviolet band to the short wave infrared band.

[0011] The application introduces n-type semiconductor layer including ZnO and p-type semiconductor layer including rare earth element doped Te in photoelectric detector, ZnO and rare earth doped Te form type II band alignment, Fermi level of n-type ZnO semiconductor is close to conduction band top, Fermi level of p-type Te semiconductor is close to valence band bottom, Fermi level difference causes charge redistribution until equilibrium state, built-in electric field from ZnO to Te is formed, the electric field can drive minority carrier diffusion under no light and zero bias, the carrier diffusion forms weak reverse dark current, when light source irradiates on the detector, photo-generated electron-hole pairs are produced, type II band alignment is beneficial to separate electrons and holes, built-in electric field drives photo-generated electrons to n-ZnO (to buffer layer) and holes to p-Te (to metal electrode), forming reverse photoelectric current. At the same time, Te can produce photothermal effect due to large Seebeck coefficient, producing forward current, photovoltaic effect of p-n junction and photothermal effect of Te film compete with each other, by adjusting thickness of Te film, polarity conversion point can be adjusted to move to shorter (or longer) wavelength, finally realizing current polarity change under different wavelengths.

[0012] Preferably, the material of the substrate comprises sapphire or quartz glass.

[0013] Preferably, the material of the buffer layer comprises any one of indium tin oxide, indium zinc oxide, aluminum doped zinc oxide, nickel oxide or indium tin zinc oxide.

[0014] Preferably, the rare earth element comprises Yb and / or Er.

[0015] Preferably, the content of the rare earth element in the p-type semiconductor layer is 0.5wt%-1wt%.

[0016] Preferably, the material of the metal electrode comprises any one of gold, silver, platinum or palladium or an alloy of at least two of them.

[0017] Preferably, the thickness of the buffer layer is 170nm-270nm.

[0018] Preferably, the thickness of the n-type semiconductor layer is 200nm-300nm.

[0019] Preferably, the thickness of the p-type semiconductor layer is 100nm-200nm.

[0020] Preferably, the thickness of the metal electrode is 50nm-100nm.

[0021] Preferably, the resistance of the buffer layer is 5Ω-7Ω.

[0022] Preferably, the light transmittance of the buffer layer is greater than 81%.

[0023] In a second aspect, the present application provides a preparation method of the bipolar response self-powered wide-spectrum photodetector according to the first aspect, the preparation method comprising:

[0024] sequentially depositing a buffer layer, an n-type semiconductor layer and a p-type semiconductor layer on a surface of a substrate; annealing; depositing a metal electrode on a surface of the p-type semiconductor layer away from the n-type semiconductor layer to obtain the bipolar response self-powered wide-spectrum photodetector; and the deposition of the buffer layer, the n-type semiconductor layer and the p-type semiconductor layer each independently comprises a magnetron sputtering process.

[0025] Preferably, during the magnetron sputtering process, the substrate is placed on a rotating heating stage and preheated to a deposition temperature for 5-15 min.

[0026] Preferably, the rotating speed of the rotating heating stage is 10-20 rpm.

[0027] Preferably, the distance between the substrate and the target material is 3-10 cm.

[0028] Preferably, during the deposition process, the flow rate of Ar is 30-70 sccm.

[0029] Preferably, the deposition temperature is 50-100℃.

[0030] Preferably, before the magnetron sputtering process, the vacuum degree in the chamber is less than 10 -3 Pa.

[0031] Preferably, during the magnetron sputtering process, the vacuum degree in the chamber is 0.5-1 Pa.

[0032] Preferably, after the deposition of the p-type semiconductor layer, the vacuum degree in the chamber is maintained to be less than 10 -3 Pa until the temperature is lowered to room temperature.

[0033] Preferably, the annealing method comprises vacuum thermal annealing.

[0034] Preferably, the annealing temperature is 200-300℃.

[0035] Preferably, the annealing time is 5-15 min.

[0036] Preferably, during the deposition of the buffer layer, the power source for magnetron sputtering is a radio frequency power source, and the output power of the radio frequency power source is 120-180 W.

[0037] Preferably, the deposition time of the buffer layer is 15-45 min.

[0038] Preferably, the n-type semiconductor layer is deposited by magnetron sputtering, and the power source for the magnetron sputtering is a radio frequency power source, and the output power of the radio frequency power source is 100-150 W.

[0039] Preferably, the deposition time of the n-type semiconductor layer is 40-80 min.

[0040] Preferably, the p-type semiconductor layer is deposited by magnetron sputtering, and the magnetron sputtering mode comprises simultaneously using a radio frequency power source to sputter a Te target and a direct current power source to sputter a rare earth target, and the output power of the radio frequency power source is 80-120 W, and the output power of the direct current power source is 6-10 W.

[0041] Preferably, the deposition time of the p-type semiconductor layer is 10-20 min.

[0042] Preferably, the preparation method further comprises polishing both sides of the substrate before depositing the buffer layer.

[0043] Preferably, the preparation method further comprises washing and drying the polished substrate.

[0044] Preferably, the washing comprises sequentially performing ultrasonic cleaning of the substrate using acetone, ethanol and deionized water.

[0045] Preferably, the time for performing ultrasonic cleaning of the substrate using acetone, ethanol and deionized water is independently 5-15 min.

[0046] Preferably, the drying mode comprises nitrogen blowing.

[0047] Compared with the prior art, the present application has the following beneficial effects:

[0048] The present application introduces an n-type semiconductor layer comprising ZnO and a p-type semiconductor layer comprising rare earth element-doped Te into a photodetector, utilizes the photovoltaic effect of the p-n junction to form a reverse photocurrent, utilizes the photothermoelectric effect of the Te thin film to generate a forward current, integrates the photovoltaic effect and the photothermoelectric effect in one device, and finally obtains a multifunctional bipolar response self-powered wide-spectrum photodetector. BRIEF DESCRIPTION OF DRAWINGS

[0049] Figure 1 is a bipolar response self-powered wide-spectrum photodetector test process schematic diagram provided by the embodiment 1 of the present application.

[0050] Figure 2 is an iv-t graph of the bipolar response self-powered wide-spectrum photodetector provided by the embodiment 1 of the present application under zero bias ultraviolet 254 nm light irradiation.

[0051] Figure 3The iv-t graph of the bipolar response self-powered wide spectrum photodetector provided for the embodiment 1 of the present application under zero bias ultraviolet 365nm light illumination.

[0052] Figure 4 The iv-t graph of the bipolar response self-powered wide spectrum photodetector provided for the embodiment 1 of the present application under zero bias visible 530nm light illumination.

[0053] Figure 5 The iv-t graph of the bipolar response self-powered wide spectrum photodetector provided for the embodiment 1 of the present application under zero bias infrared 800nm light illumination.

[0054] Figure 6 The responsivity graph of the bipolar response self-powered wide spectrum photodetector provided for the embodiment 1 of the present application under different wavelength light illumination.

[0055] Wherein, 1-substrate; 2-buffer layer; 3-n-type semiconductor layer; 4-p-type semiconductor layer; 5-metal electrode. DETAILED DESCRIPTION

[0056] The technical solutions of the present application will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only to help understand the present application, and should not be regarded as specific limitations of the present application.

[0057] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application; the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion.

[0058] In the description of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0059] "Ranges" disclosed herein can be defined, for example, by both a lower and an upper limit. Ranges can be inclusive or exclusive of the endpoints, and any intervening range or point. Unless otherwise specifically stated, the use of a range includes each independent number within the range and each combination of these numbers. For example, if a range is stated as 60-120 and 80-110, it is understood that the ranges 60-110 and 80-120 are also contemplated. Additionally, if a minimum range value of 1 and 2 is stated, and a maximum range value of 3, 4, and 5 is stated, then the following ranges are contemplated: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In the present application, unless otherwise stated, a numerical range "a-b" indicates a shorthand way of describing each and every number that is contained within the range, wherein a and b are both real numbers. For example, the numerical range "0-5" indicates that all real numbers contained within the range "0-5" have been listed herein, and "0-5" is merely a shorthand way of describing these numerical combinations. Additionally, when a parameter is stated to be an integer > 2, it is equivalent to stating that the parameter is, for example, an integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For example, when a parameter is stated to be an integer selected from "2-10", it is equivalent to stating that the parameter is an integer 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0060] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions.

[0061] In one specific embodiment, the present application provides a bipolar response self-powered wide-spectrum photodetector, characterized in that the bipolar response self-powered wide-spectrum photodetector comprises a substrate, a buffer layer, an n-type semiconductor layer, and a p-type semiconductor layer which are sequentially stacked; a metal electrode is arranged on the side surface of the p-type semiconductor layer away from the n-type semiconductor layer; the material of the n-type semiconductor layer comprises ZnO; and the material of the p-type semiconductor layer comprises a rare earth element doped Te.

[0062] The present application introduces an n-type semiconductor layer including ZnO and a p-type semiconductor layer including rare earth element doped Te in a photodetector. The ZnO and the rare earth doped Te form a type II band alignment, the Fermi level of the n-type ZnO semiconductor is close to the conduction band top, and the Fermi level of the p-type Te semiconductor is close to the valence band bottom. The Fermi level difference causes charge redistribution until an equilibrium state is reached, forming a built-in electric field from ZnO to Te. Under no light and zero bias, the electric field can drive minority carrier diffusion. This carrier diffusion forms a weak reverse dark current. When a light source is irradiated on the detector, photo-generated electron-hole pairs are generated. The type II band alignment is conducive to the separation of electrons and holes. The built-in electric field drives the photo-generated electrons to the n-ZnO (to the buffer layer) and the holes to the p-Te (to the metal electrode), forming a reverse photo current. At the same time, Te can generate a photothermal effect due to its large Seebeck coefficient, generating a forward current. The photovoltaic effect of the p-n junction and the photothermal effect of the Te film compete with each other. By adjusting the thickness of the Te film, the polarity conversion point can be adjusted to move to a shorter (or longer) wavelength, and finally the current polarity change at different wavelengths can be realized.

[0063] In some embodiments, the substrate is made of sapphire or quartz glass.

[0064] In some embodiments, the buffer layer is made of any one of indium tin oxide (ITO), indium zinc oxide (IZO), aluminum-doped zinc oxide (AZO), nickel oxide, or indium tin zinc oxide (ITZO).

[0065] In some embodiments, the rare earth element includes Yb and / or Er.

[0066] In some embodiments, the content of the rare earth element in the p-type semiconductor layer is 0.5wt% to 1wt%, for example, it can be 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt% or 1wt%.

[0067] In some embodiments, the metal electrode is made of any one of gold, silver, platinum or palladium, or an alloy of at least two of them.

[0068] In some embodiments, the thickness of the buffer layer is 170nm to 270nm, for example, it can be 170nm, 180nm, 190nm, 200nm, 210nm, 220nm, 230nm, 240nm, 250nm, 260nm or 270nm.

[0069] In some embodiments, the n-type semiconductor layer has a thickness of 200-300 nm, for example, 200 nm, 210 nm, 220 nm, 230 nm, 240 nm, 250 nm, 260 nm, 270 nm, 280 nm, 290 nm or 300 nm.

[0070] In some embodiments, the p-type semiconductor layer has a thickness of 100-200 nm, for example, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm or 200 nm.

[0071] In some embodiments, the metal electrode has a thickness of 50-100 nm, for example, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm or 100 nm.

[0072] In some embodiments, the buffer layer has a resistance of 5-7 Ω, for example, 5 Ω, 5.5 Ω, 6 Ω, 6.5 Ω or 7 Ω.

[0073] In some embodiments, the buffer layer has a light transmittance of greater than 81%, for example, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89% or 90%.

[0074] In another specific embodiment, the present application provides a preparation method of the bipolar response self-powered wide-spectrum photodetector as described in the foregoing specific embodiment, and the preparation method comprises:

[0075] sequentially depositing a buffer layer, an n-type semiconductor layer and a p-type semiconductor layer on a surface of a substrate; annealing; depositing a metal electrode on a surface of the p-type semiconductor layer away from the n-type semiconductor layer to prepare the bipolar response self-powered wide-spectrum photodetector; and the deposition of the buffer layer, the n-type semiconductor layer and the p-type semiconductor layer each independently comprises magnetron sputtering.

[0076] In some embodiments, during the magnetron sputtering, the substrate is placed on a rotary heating stage, preheated to a deposition temperature and maintained for 5-15 min, for example, 5 min, 7 min, 9 min, 11 min, 13 min or 15 min.

[0077] In some embodiments, the rotary heating stage has a rotation speed of 10-20 rpm, for example, 10 rpm, 11 rpm, 12 rpm, 13 rpm, 14 rpm, 15 rpm, 16 rpm, 17 rpm, 18 rpm, 19 rpm or 20 rpm.

[0078] In some embodiments, the distance between the substrate and the target is 3 cm to 10 cm, for example, it can be 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm or 10 cm.

[0079] In some embodiments, the flow rate of Ar during the deposition process is 30 sccm to 70 sccm, for example, it can be 30 sccm, 35 sccm, 40 sccm, 45 sccm, 50 sccm, 55 sccm, 60 sccm, 65 sccm or 70 sccm.

[0080] In some embodiments, the temperature during the deposition is 50℃ to 100℃, for example, it can be 50℃, 52℃, 54℃, 56℃, 58℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃ or 100℃.

[0081] In some embodiments, the vacuum degree in the chamber before the magnetron sputtering process is less than 10 -3 Pa, for example, it can be 5×10 -4 Pa, 6×10 -4 Pa, 7×10 -4 Pa, 8×10 -4 Pa or 9×10 -4 Pa.

[0082] In some embodiments, the vacuum degree in the chamber during the magnetron sputtering process is 0.5 Pa to 1 Pa, for example, it can be 0.5 Pa, 0.6 Pa, 0.7 Pa, 0.8 Pa, 0.9 Pa or 1 Pa.

[0083] In some embodiments, after the deposition of the p-type semiconductor layer is completed, the vacuum degree in the chamber is kept less than 10 -3 Pa to cool down to room temperature.

[0084] In the present application, the room temperature refers to 25℃ to 35℃, for example, it can be 25℃, 26℃, 27℃, 28℃, 29℃ or 30℃.

[0085] In some embodiments, the annealing method includes vacuum thermal annealing.

[0086] In some embodiments, the annealing temperature is 200℃ to 300℃, for example, it can be 200℃, 210℃, 220℃, 230℃, 240℃, 250℃, 260℃, 270℃, 280℃, 290℃ or 300℃.

[0087] In some embodiments, the annealing time is 5 min to 15 min, for example, it can be 5 min, 7 min, 9 min, 11 min, 13 min or 15 min.

[0088] In some embodiments, during the deposition of the buffer layer, the power source for magnetron sputtering is a radio frequency power source, and the output power of the radio frequency power source is 120 W to 180 W, for example, it can be 120 W, 130 W, 140 W, 150 W, 160 W, 170 W or 180 W.

[0089] In some embodiments, the deposition time of the buffer layer is 15 min to 45 min, for example, it can be 15 min, 20 min, 25 min, 30 min, 35 min, 40 min or 45 min.

[0090] In some embodiments, during the deposition of the n-type semiconductor layer, the power source for magnetron sputtering is a radio frequency power source, and the output power of the radio frequency power source is 100 W to 150 W, for example, it can be 100 W, 110 W, 120 W, 130 W, 140 W or 150 W.

[0091] In some embodiments, the deposition time of the n-type semiconductor layer is 40 min to 80 min, for example, it can be 40 min, 45 min, 50 min, 55 min, 60 min, 65 min, 70 min, 75 min or 80 min.

[0092] In some embodiments, during the deposition of the p-type semiconductor layer, the magnetron sputtering mode comprises simultaneously using a radio frequency power source to sputter a Te target and a direct current power source to sputter a rare earth target, the output power of the radio frequency power source is 80 W to 120 W, for example, it can be 80 W, 85 W, 90 W, 95 W, 100 W, 105 W, 110 W, 115 W or 120 W, and the output power of the direct current power source is 6 W to 10 W, for example, it can be 6 W, 6.5 W, 7 W, 7.5 W, 8 W, 8.5 W, 9 W, 9.5 W or 10 W.

[0093] In some embodiments, the deposition time of the p-type semiconductor layer is 10 min to 20 min, for example, it can be 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min, 19 min or 20 min.

[0094] In some embodiments, the preparation method further comprises polishing both sides of the substrate before depositing the buffer layer.

[0095] In some embodiments, the preparation method further comprises washing and drying the polished substrate.

[0096] In some embodiments, the washing includes sequentially using acetone, ethanol and deionized water to ultrasonically clean the substrate.

[0097] In some embodiments, the time for ultrasonically cleaning the substrate using acetone, ethanol and deionized water is each independently 5-15 min, for example, can be 5 min, 7 min, 9 min, 11 min, 13 min or 15 min.

[0098] In some embodiments, the drying method includes nitrogen blowing.

[0099] The numerical ranges recited herein include all values from and including the lower and upper values. This is true even if the values included in the lower or upper range are outside of the recited range. The ranges are presented essentially to provide some guidance as to the scope of the present application. The end values of the ranges are provided for purposes of clarity.

[0100] Example 1

[0101] The embodiment provides a bipolar response self-powered wide-spectrum photodetector, which comprises a substrate, a buffer layer with a thickness of 220 nm, an n-type semiconductor layer with a thickness of 250 nm and a p-type semiconductor layer with a thickness of 150 nm arranged in sequence; and a metal electrode with a thickness of 75 nm is arranged on a side surface of the p-type semiconductor layer away from the n-type semiconductor layer.

[0102] The substrate 1 is a 20*10*1mm double-side polished sapphire substrate, the buffer layer is made of indium tin oxide with a resistance of 6Ω and a light transmittance of 82%, the n-type semiconductor layer is made of ZnO, the p-type semiconductor layer is made of Yb-doped Te with a Yb content of 0.78wt%, and the metal electrode is made of gold.

[0103] The embodiment further provides a preparation method of a bipolar response self-powered wide-spectrum photodetector, which comprises the following steps:

[0104] (1) sequentially using acetone, ethanol and deionized water to ultrasonically clean a 20*10*1mm double-side polished sapphire substrate for 10 min, and blowing with nitrogen.

[0105] (2) growing an ITO buffer layer on the sapphire substrate by using a magnetron sputtering technology; before deposition, heating the substrate to 80℃ for 10 min, setting the rotating speed of a rotating heating table to 15 rpm, setting the distance between the substrate and the ITO target material to 5 cm, setting the flow rate of Ar to 50sccm, and setting the vacuum degree of the magnetron sputtering system to 8*10 -4Pa, the vacuum degree during deposition is 0.8 Pa, the output power of the radio frequency power supply is set to 150 W during deposition, and deposition is performed for 30 min.

[0106] (3) ZnO thin film is grown on the surface of the ITO buffer layer prepared in step (2) by using a magnetron sputtering technique, the output power of the radio frequency power supply is set to 120 W, and deposition is performed for 60 min.

[0107] (4) Yb-doped Te thin film is grown on the surface of the ZnO thin film prepared in step (3) by using a magnetron sputtering technique, a radio frequency power supply is used to sputter a Te target, and a direct current power supply is used to sputter a rare earth target, the output power of the radio frequency power supply is set to 100 W, the output power of the direct current power supply is set to 8 W, deposition is performed for 15 min, and after deposition, the vacuum is broken after cooling to room temperature.

[0108] (5) The deposited sample is placed in a tubular furnace for vacuum thermal annealing, the annealing temperature is set to 250 ℃, and annealing is performed for 12 min.

[0109] (6) An electrode pattern with a specific pattern structure is obtained on the surface of the p-type semiconductor layer by using a maskless lithography technique, and then a gold point electrode is deposited on the surface of the p-type semiconductor layer by using a magnetron sputtering technique, thereby preparing the bipolar response self-powered wide-spectrum photodetector.

[0110] Embodiment 2

[0111] The embodiment provides a bipolar response self-powered wide-spectrum photodetector, which comprises a substrate, a buffer layer with a thickness of 170 nm, an n-type semiconductor layer with a thickness of 200 nm and a p-type semiconductor layer with a thickness of 100 nm which are sequentially stacked; and a metal electrode with a thickness of 50 nm is arranged on the side surface of the p-type semiconductor layer away from the n-type semiconductor layer.

[0112] The substrate is a 20*10*1mm double-side polished sapphire substrate, the buffer layer is made of IZO, the resistance is 7Ω, and the light transmittance is 83%, the n-type semiconductor layer is made of ZnO, and the p-type semiconductor layer is made of Er-doped Te, wherein the content of Er is 0.5wt%.

[0113] The embodiment further provides a preparation method of a bipolar response self-powered wide-spectrum photodetector, which comprises the following steps:

[0114] (1) A 20*10*1mm double-side polished sapphire substrate is ultrasonically cleaned with acetone, ethanol and deionized water for 12 min, and then dried with nitrogen.

[0115] (2) IZO buffer layer is grown on the sapphire substrate by magnetron sputtering technology. Before deposition, the substrate is heated to 50℃ and kept for 5 min, the rotation speed of the rotating heating table is set to 10 rpm, the distance between the substrate and the ITO target is 3 cm, the flow rate of Ar is 30 sccm, before deposition, the vacuum degree of the magnetron sputtering system is 7*10 -4 0.5 Pa, during deposition, the output power of the radio frequency power supply is set to 120 W, and deposition is performed for 15 min.

[0116] (3) ZnO thin film is grown on the IZO buffer layer prepared in step (2) by magnetron sputtering technology, the output power of the radio frequency power supply is set to 100 W, and deposition is performed for 40 min.

[0117] (4) Er-doped Te thin film is grown on the ZnO thin film prepared in step (3) by magnetron sputtering technology, the radio frequency power supply is used to sputter the Te target and the direct current power supply is used to sputter the rare earth target, the output power of the radio frequency power supply is set to 80 W, the output power of the direct current power supply is set to 6 W, deposition is performed for 10 min, and after deposition, the vacuum is broken after cooling to room temperature.

[0118] (5) The deposited sample is placed in a tubular furnace for vacuum thermal annealing, the annealing temperature is set to 200℃, and annealing is performed for 10 min.

[0119] (6) An electrode pattern with a specific pattern structure is obtained on the surface of the p-type semiconductor layer by a maskless lithography technology, and then a gold point electrode is deposited on the surface of the p-type semiconductor layer by magnetron sputtering technology, thereby preparing the bipolar response self-powered wide-spectrum photodetector.

[0120] Embodiment 3

[0121] The embodiment provides a bipolar response self-powered wide-spectrum photodetector, which comprises a substrate, a buffer layer with a thickness of 270 nm, an n-type semiconductor layer with a thickness of 300 nm and a p-type semiconductor layer with a thickness of 200 nm which are sequentially stacked; a metal electrode with a thickness of 100 nm is arranged on the side surface of the p-type semiconductor layer away from the n-type semiconductor layer.

[0122] The substrate is a 20*10*1mm double-side polished sapphire substrate, the buffer layer is made of ITO with a resistance of 5Ω and a light transmittance of 81.5%, the n-type semiconductor layer is made of ZnO, and the p-type semiconductor layer is made of Yb-doped Te, wherein the content of Yb is 1wt%.

[0123] The embodiment also provides a preparation method of a bipolar response self-powered wide-spectrum photodetector, which comprises the following steps:

[0124] (1) The 20*10*1mm, double-side polished sapphire substrate was cleaned by ultrasonic cleaning with acetone, ethanol and deionized water for 10min, and dried by nitrogen.

[0125] (2) The ITO buffer layer was grown on the sapphire substrate by magnetron sputtering technology. Before deposition, the substrate was heated to 100℃ and kept for 15min, the rotation speed of the rotating heating table was set to 20rpm, the distance between the substrate and the ITO target was 10cm, the flow rate of Ar was 70sccm, and the vacuum degree of the magnetron sputtering system before deposition was 9.5*10 -4 Pa, and the vacuum degree during deposition was 1Pa. During deposition, the output power of the radio frequency power supply was set to 180W, and the deposition time was 45min.

[0126] (3) The ZnO thin film was grown on the buffer layer prepared in step (2) by magnetron sputtering technology, and the output power of the radio frequency power supply was set to 150W, and the deposition time was 80min.

[0127] (4) The Yb-doped Te thin film was grown on the ZnO thin film prepared in step (3) by magnetron sputtering technology, and the radio frequency power supply was used to sputter the Te target and the direct current power supply was used to sputter the rare earth target, the output power of the radio frequency power supply was set to 120W, the output power of the direct current power supply was set to 10W, the deposition time was 20min, and after the deposition was completed, the vacuum was broken after cooling to room temperature.

[0128] (5) The deposited sample was placed in a tubular furnace for vacuum heat annealing, and the annealing temperature was set to 300℃, and the annealing time was 15min.

[0129] (6) The electrode pattern with a specific pattern structure was obtained on the surface of the p-type semiconductor layer by maskless lithography technology, and then the gold point electrode was deposited on the surface of the p-type semiconductor layer by magnetron sputtering technology, thereby preparing the bipolar response self-powered wide-spectrum photodetector.

[0130] Example 4

[0131] The bipolar response self-powered wide-spectrum photodetector provided in this embodiment is the same as that in Example 1, except that the thickness of the ITO buffer layer is 350nm, the resistance is 4Ω, and the light transmittance is 80%, i.e., less than 81%.

[0132] Example 5

[0133] The bipolar response self-powered wide-spectrum photodetector provided in this embodiment is the same as that in Example 1, except that the thickness of the n-type semiconductor layer is 150nm.

[0134] Example 6

[0135] The embodiment provides a bipolar response self-powered wide-spectrum photodetector, wherein the thickness of the n-type semiconductor layer is 350 nm, and the rest is the same as in the embodiment 1.

[0136] Embodiment 7

[0137] The embodiment provides a bipolar response self-powered wide-spectrum photodetector, wherein the thickness of the p-type semiconductor layer is 80 nm, and the rest is the same as in the embodiment 1.

[0138] Embodiment 8

[0139] The embodiment provides a bipolar response self-powered wide-spectrum photodetector, wherein the thickness of the p-type semiconductor layer is 120 nm, and the rest is the same as in the embodiment 1.

[0140] Embodiment 9

[0141] The embodiment provides a bipolar response self-powered wide-spectrum photodetector, wherein the annealing temperature in the preparation process is 180 DEG C, and the rest is the same as in the embodiment 1.

[0142] Embodiment 10

[0143] The embodiment provides a bipolar response self-powered wide-spectrum photodetector, wherein the annealing temperature in the preparation process is 320 DEG C, and the rest is the same as in the embodiment 1.

[0144] Embodiment 11

[0145] The embodiment provides a bipolar response self-powered wide-spectrum photodetector, wherein the output power of the radio frequency power supply in the preparation process of depositing the n-type semiconductor layer is 80 W, and the rest is the same as in the embodiment 1.

[0146] Embodiment 12

[0147] The embodiment provides a bipolar response self-powered wide-spectrum photodetector, wherein the output power of the radio frequency power supply in the preparation process of depositing the n-type semiconductor layer is 160 W, and the rest is the same as in the embodiment 1.

[0148] Embodiment 13

[0149] The embodiment provides a bipolar response self-powered wide-spectrum photodetector, wherein the output power of the radio frequency power supply in the preparation process of depositing the p-type semiconductor layer is 70 W, and the output power of the direct current power supply is 5 W, and the rest is the same as in the embodiment 1.

[0150] Embodiment 14

[0151] The embodiment provides a bipolar response self-powered wide-spectrum photodetector, which is the same as embodiment 1 except that the output power of the radio frequency power supply is 125 W and the output power of the direct current power supply is 12 W during preparation of the p-type semiconductor layer.

[0152] Comparative example 1

[0153] The comparative example provides a photodetector, which is the same as embodiment 1 except that the material of the n-type semiconductor layer is replaced by InAs.

[0154] Comparative example 2

[0155] The comparative example provides a photodetector, which is the same as embodiment 1 except that the material of the p-type semiconductor layer is replaced by GaN.

[0156] Comparative example 3

[0157] The comparative example provides a photodetector, which is the same as embodiment 1 except that the material of the p-type semiconductor layer is Te and no rare earth element is doped.

[0158] Performance test:

[0159] As shown in Figure 1 , the photodetectors provided by all the above examples and comparative examples and having the substrate 1, the buffer layer 2, the n-type semiconductor layer 3, the p-type semiconductor layer 4 and the metal electrode 5 arranged in sequence are fixed on an electron probe table, then the positive and negative electrodes of the probe table are connected to the metal electrode 5 and the buffer layer 2 respectively. Monochromatic light sources with different wavelengths are irradiated on the photodetector prepared in embodiment 1, and a semiconductor analyzer is used to analyze the photoelectric performance, which specifically includes:

[0160] (1) The output voltage of the semiconductor parameter analyzer is set to 0 V, that is, zero bias, and the values of the photocurrent generated by the photodetector under the irradiation of ultraviolet light 254 nm, ultraviolet light 365 nm, visible light 530 nm and infrared light 800 nm are recorded, the photocurrent values are shown in Table 1, and the iv-t images of the photodetector provided by embodiment 1 under the irradiation of the above wavelengths are shown in Figures 2 to 5 .

[0161] The responsivity of the photodetector provided by embodiment 1 under the irradiation of different wavelengths is shown in Figure 6 , and with the increase of the wavelength of the radiation light source, the photocurrent of the photodetector changes in polarity, showing the characteristics of bipolar response.

[0162] Table 1

[0163]

[0164]

[0165] According to the test results shown in Table 1 and Figures 2 to 6 According to the test results shown in Table 1 and

[0166] According to the test results of Example 1 and Comparative Examples 1 to 3 in Table 1, if the material of the n-type semiconductor layer and the p-type semiconductor layer is not ZnO and rare earth doped Te as defined in the present application, the photovoltaic effect of the p-n junction and the photothermoelectric effect of the Te film cannot be formed at the same time, so that the bipolar response in a wide spectral range cannot be realized.

[0167] According to the test results of Example 1 and Example 4, if the light transmittance of the buffer layer is less than 81%, a large amount of incident light is absorbed or reflected in the buffer layer, resulting in a decrease in photo-generated carriers and photocurrent.

[0168] According to the test results of Example 1 and Example 5 and Example 6, if the thickness of the n-type semiconductor layer is too large or too small, the thickness of the absorption layer is too small, the incident light cannot be fully absorbed, or although the light is absorbed, the photo-generated electrons / holes have to cross a thicker material to reach the electrode, ultimately resulting in a decrease in effective photocurrent in the ultraviolet band.

[0169] According to the test results of Example 1 and Example 7 and Example 8, if the thickness of the p-type semiconductor layer is too large or too small, the effective photocurrent in the infrared band decreases, and the polarity switching point moves to a shorter (longer) wavelength.

[0170] According to the test results of Example 1 and Example 9 and Example 10, if the annealing temperature is too high or too low, the film defects increase or the crystallization is incomplete, and the photocurrent decreases significantly.

[0171] According to the test results of Example 1 and Examples 11 and 12, if the output power of the radio frequency power source is too large or too small when depositing the n-type semiconductor layer, the film thickness changes, the defects increase, and the ultraviolet band photocurrent significantly decreases.

[0172] According to the test results of Example 1 and Examples 13 and 14, if the output power of the radio frequency power source and the direct current power source is too large or too small when depositing the p-type semiconductor layer, the film thickness changes, the defects increase, the infrared band photocurrent significantly decreases, and the polarity conversion point moves to a shorter (longer) wavelength.

[0173] The applicant states that the above description is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. It should be understood by those skilled in the art that any changes or replacements within the technical scope disclosed by the present application can be easily thought of by any person skilled in the art, and all such changes or replacements fall within the protection scope and disclosure scope of the present application.

Claims

1. A bipolar-response self-powered broadband photodetector, characterized in that, The bipolar-response self-powered broadband photodetector comprises a substrate, a buffer layer, an n-type semiconductor layer, and a p-type semiconductor layer stacked sequentially. A metal electrode is disposed on the surface of the p-type semiconductor layer away from the n-type semiconductor layer; The material of the n-type semiconductor layer includes ZnO; The p-type semiconductor layer is made of rare earth element-doped Te.

2. The bipolar-response self-powered broadband photodetector as described in claim 1, characterized in that, The substrate material includes sapphire or quartz glass; And / or, the material of the buffer layer includes any one of indium tin oxide, indium zinc oxide, aluminum-doped zinc oxide, nickel oxide, or indium tin zinc oxide; And / or, in the p-type semiconductor layer, the rare earth elements include Yb and / or Er; And / or, the content of rare earth elements in the p-type semiconductor layer is 0.5wt% to 1wt%; And / or, the metal electrode is made of any one or an alloy of at least two of gold, silver, platinum or palladium.

3. The bipolar-response self-powered broadband photodetector as described in claim 1 or 2, characterized in that, The thickness of the buffer layer is 170nm to 270nm; And / or, the thickness of the n-type semiconductor layer is 200nm to 300nm; And / or, the thickness of the p-type semiconductor layer is 100nm to 200nm; And / or, the thickness of the metal electrode is 50 nm to 100 nm; And / or, the resistance of the buffer layer is 5Ω to 7Ω; And / or, the light transmittance of the buffer layer is greater than 81%.

4. A method for fabricating a bipolar-response self-powered broadband photodetector as described in any one of claims 1 to 3, characterized in that, The preparation method includes: A buffer layer, an n-type semiconductor layer, and a p-type semiconductor layer are sequentially deposited on the substrate surface; annealing is performed; a metal electrode is deposited on the surface of the p-type semiconductor layer away from the n-type semiconductor layer to prepare the bipolar-response self-powered broadband photodetector. The deposition methods for the buffer layer, the n-type semiconductor layer, and the p-type semiconductor layer each independently include magnetron sputtering deposition.

5. The preparation method according to claim 4, characterized in that, The deposition temperature is 50℃~100℃; And / or, the vacuum level in the cavity is less than 10 before the magnetron sputtering coating. -3 Pa; And / or, during the magnetron sputtering coating process, the vacuum level in the cavity is 0.5 Pa to 1 Pa; And / or, after the p-type semiconductor layer deposition is completed, the vacuum level inside the cavity is maintained at less than 10. -3 Pa was cooled to room temperature.

6. The preparation method according to claim 4 or 5, characterized in that, The annealing method includes vacuum thermal annealing; And / or, the annealing temperature is 200℃~300℃; And / or, the annealing time is 5 min to 15 min.

7. The preparation method according to any one of claims 4 to 6, characterized in that, During the deposition of the buffer layer, the magnetron sputtering is powered by an RF power supply with an output power of 120W to 180W. And / or, the buffer layer is deposited for 15 min to 45 min.

8. The preparation method according to any one of claims 4 to 7, characterized in that, During the deposition of the n-type semiconductor layer, the magnetron sputtering power supply is an radio frequency power supply with an output power of 100W to 150W. And / or, the deposition time of the n-type semiconductor layer is 40 min to 80 min.

9. The preparation method according to any one of claims 4 to 8, characterized in that, During the deposition of the p-type semiconductor layer, the magnetron sputtering method includes simultaneously using an RF power supply to sputter the Te target and a DC power supply to sputter the rare earth target. The output power of the RF power supply is 80W to 120W, and the output power of the DC power supply is 6W to 10W. And / or, the deposition time of the p-type semiconductor layer is 10 min to 20 min.

10. The preparation method according to any one of claims 4 to 9, characterized in that, The preparation method further includes washing and drying the substrate before depositing the buffer layer.

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