CN109585593B - A spontaneous polarization field-enhanced ultraviolet light detector based on BeZnOS quaternary alloy and its preparation method - Google Patents

Abstract

The invention discloses a spontaneous polarization field-enhanced ultraviolet light detector based on BeZnOS quaternary alloy and a preparation method thereof. The detector sequentially includes an m-plane sapphire substrate, an active layer, and a pair of parallel metal electrodes from bottom to top, wherein: the active layer is an m-plane BeZnOS quaternary alloy thin film, and the parallel metal electrodes are perpendicular to the The c-axis direction of BeZnOS quaternary alloy thin films. The invention grows an epitaxial m-plane BeZnOS film on a single-crystal m-plane sapphire, vapor-deposits a metal electrode perpendicular to the c-axis of the film, fully utilizes the superposition of the spontaneous polarization electric field and the external electric field to enhance the separation of photogenerated carriers, and enhances the light detection capability. In addition, the MSM structure ultraviolet light detector prepared by the invention has a simple structure and a simple manufacturing process. The detector has good detection capability for ultraviolet light with a wavelength of 300 nm, and has fast response speed, small dark current and stable performance.

Description

A Spontaneous Polarization Field-Enhanced Ultraviolet Photodetector Based on BeZnOS Quaternary Alloy and preparation method thereof

technical field

The invention belongs to the technical field of semiconductor detectors, in particular to an ultraviolet light detector with an MSM structure, and more particularly, the invention relates to a spontaneous polarization field-enhanced ultraviolet light detector based on BeZnOS quaternary alloy and the same Preparation.

Background technique

BeZnOS quaternary alloy is a semiconductor material with wide band gap and high visible light transmittance, which can be used in ultraviolet to solar blind region light-emitting devices or photodetection devices. Since BeZnOS quaternary alloy has hexagonal wurtzite structure like ZnO crystal, its interior is alternately arranged by O(S) atomic plane and Zn(Be) atomic plane, and Zn(Be)-O(S) bond has polarity, A large number of neatly arranged Zn(Be)-O(S) bonds lead to the existence of a spontaneous polarization field in the c-axis direction of BeZnOS. This spontaneous polarization field existing in the entire BeZnOS crystal can effectively promote the separation and separation of photogenerated carriers. Therefore, the spontaneously polarized field-enhanced detector developed based on the m-plane BeZnOS quaternary film theoretically has better detection capability than the ordinary c-plane BeZnOS film-based detector. When using the PLD method to grow BeZnOS thin films on m-plane sapphire, the surface of the film is m-plane, and the c-axis of the film is perpendicular to the c-axis of the sapphire, and the c-axis of the film is parallel to the surface. ) and there is a spontaneously polarized electric field in the parallel direction.

The metal-semiconductor-metal (MSM) structure detector has the advantages of simple structure and high detection efficiency. The performance of the obtained detector can be regulated by controlling parameters such as metal type and channel width. When a parallel electrode perpendicular to the c-axis of the film is designed and fabricated on the surface of the m-plane BeZnOS film, an enhanced MSM ultraviolet detector can be obtained by utilizing the spontaneous polarization electric field of the film.

In addition, the prior art with publication number CN 102412334 A discloses a BeZnO-based MSM structure ultraviolet light detector and a preparation method, the detector includes a substrate and an epitaxial layer grown on the substrate, the epitaxial The layer includes a stress buffer layer and a BeZnO doped layer disposed on the stress buffer layer, and electrodes with an interdigitated structure or a gap structure are plated on the BeZnO doped layer. However, this technology uses a buffer layer inserted between the active layer and the substrate to improve the crystal quality, which greatly increases the complexity of the process. In addition, this technology only directly prepares the film into a detector, and does not consider the polarity of the film. If it uses c-plane sapphire as the substrate, the obtained c-plane BeZnO is a polar plane epitaxial layer, which will produce the quantum Stark effect for quantum well light-emitting devices, that is, the spontaneous polarization field in the plane will spatially separate electrons and Holes reduce the recombination probability of carriers, thereby reducing the luminous intensity. At the same time, the spontaneous polarization field will bend the energy band at the quantum well and reduce the band gap, thereby making the emission wavelength longer, that is, a red shift occurs.

The research group of the inventor of the present application has applied for a patent application entitled "a BeZnOS compound semiconductor material, its preparation method and application (publication number CN 105734491 A)" in the early stage, and the BeO and ZnS are prepared in proportion The quaternary compound semiconductor material achieves effects such as free regulation of the ZnO band gap through the synergistic effect of Be and S compound substitution, and the BeZnOS quaternary compound prepared by the invention can be used for ultraviolet to solar blind area light-emitting devices or photodetection devices.

The present application is proposed after further in-depth research, development and innovation on the basis of the above work of the inventor.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a spontaneous polarization field-enhanced ultraviolet light detector based on BeZnOS quaternary alloy and a preparation method thereof. The invention effectively promotes the separation and transport of photogenerated carriers by utilizing the spontaneous electric field along the c-axis direction inside the BeZnOS alloy thin film, thereby constructing an m-plane BeZnOS-based ultraviolet light detector.

In order to realize the above-mentioned first purpose of the present invention, the present invention adopts following technical scheme:

A spontaneous polarization field-enhanced ultraviolet light detector based on BeZnOS quaternary alloy, the detector includes an m-plane sapphire substrate, an active layer, and a pair of parallel metal electrodes in sequence from bottom to top, wherein: the active The layer is an m-plane BeZnOS quaternary alloy thin film, and the parallel metal electrodes are perpendicular to the c-axis direction of the BeZnOS quaternary alloy thin film.

Further, in the above technical solution, the thickness of the m-plane sapphire substrate is 0.35-0.45 mm.

Further, in the above technical solution, the thickness of the active layer is 80-160 nm.

Further, in the above technical solution, the thickness of the parallel metal electrodes is 30-60 nm.

Further, in the above technical solution, the distance between the parallel metal electrodes is 10-100 μm.

Further, in the above technical solution, the parallel metal electrode material can be any one of Au, Ag or Al, preferably Al.

Another object of the present invention is to provide a method for preparing the above-mentioned spontaneously polarized field-enhanced ultraviolet light detector based on BeZnOS quaternary alloy, the method comprising the following steps:

(1) take m-plane sapphire as the substrate of thin film growth, utilize cleaning liquid to carry out ultrasonic cleaning to described substrate, dry with nitrogen gas, place in the vacuum chamber of pulsed laser deposition system immediately;

(2) adopting the method of pulsed laser ablation deposition, magnetron sputtering or electron beam evaporation to deposit on the surface of the m-plane sapphire substrate pretreated in step (1) to form an m-plane BeZnOS quaternary alloy film;

(3) determining the c-axis direction of the m-plane BeZnOS quaternary alloy thin film obtained in step (2) by using a four-circle single crystal X-ray diffractometer XRD;

(4) Using the evaporation method or the photolithography method, a pair of parallel metal electrodes are made on the surface of the BeZnOS quaternary alloy film in the direction perpendicular to the c-axis to obtain the spontaneous polarization field enhancement based on the BeZnOS quaternary alloy described in the present invention type UV detector.

Further, in the above technical solution, the cleaning solution in step (1) includes acetone, ethanol and deionized water, and the ultrasonic cleaning time is preferably 15min.

Further, in the above technical scheme, in step (2), the m-plane BeZnOS quaternary alloy film is specifically prepared by a pulsed laser ablation deposition method, and the specific process is as follows:

Using BeZnOS ceramics as the target, the substrate temperature is controlled to be 100-800°C, the pulse laser energy is 200-600mJ/Pulse, and the oxygen pressure is 0-10Pa, and the pre-treated m-plane sapphire substrate is deposited on the surface of the step (1). A BeZnOS quaternary alloy thin film is formed.

Further, in the above technical solution, the BeZnOS ceramic target material described in the step (2) is obtained by the solid-phase sintering method, and the specific method is as follows:

(a) Mix the ZnS and BeO powders evenly in a molar ratio of 99:1 to 70:30, add ultrapure water, mix them evenly again, and then place them in a ball mill for ball milling to obtain a mixed powder;

(b) drying the mixed powder in a vacuum drying oven and cooling to room temperature, then crushing and pressing into a disc;

(c) in an argon atmosphere, using sulfur powder as an oxygen scavenger, the wafer obtained in step (b) is placed in a vacuum tube furnace, and fired at 1100-1400 ° C for 2-5 hours to obtain the invention described in the present invention. BeZnOS ceramics.

Further, in the above technical solution, the temperature of the vacuum drying oven in step (b) is 110°C, and the drying time is 10h.

In the MSM ultraviolet light detector provided by the present invention, the parallel electrodes are perpendicular to the c-axis direction of the thin film crystal, so as to obtain the enhancement effect of the spontaneous polarization field.

The principle of the present invention is as follows:

In the invention, the ion radius of Be is smaller than that of Zn, and the radius of S ion is larger than that of O. After Be and S jointly replace ZnO, the two atoms complement each other, which can promote the incorporation of the two atoms at the same time, and can more simply and effectively improve the crystal quality and the band of the alloy. Gap control range.

In the present invention, the BeZnOS thin film is deposited on the m-plane sapphire substrate by using the pulsed laser deposition method. At this time, the obtained thin film is BeZnOS with m-plane orientation, and the surface has no polarity, and is used as the active layer of the detector. For BeZnOS with m-plane orientation, its c-axis is parallel to the surface of the film, and the film crystal has polarity along the c-axis. There is a spontaneously polarized electric field parallel to the surface. When the detector works under an applied electric field, when the direction of the applied electric field is consistent with the direction of the spontaneous polarization field in the film, the superposition of the two fields can accelerate the separation and transport of photogenerated carriers, thereby improving the response speed and speed of the photodetector. detection capability.

The beneficial effects of the present invention are:

1. By using BeZnOS quaternary ZnO alloy wide-bandgap semiconductor materials for photodetectors, a better crystalline quality of the film can be obtained, and a lower detection cut-off wavelength can also be obtained.

2. By growing an epitaxial m-plane BeZnOS film on single-crystal m-plane sapphire, and evaporating a metal electrode perpendicular to the c-axis of the film, the superposition effect of the spontaneous polarization electric field and the applied electric field is fully utilized to enhance the separation and transmission of photogenerated carriers , to enhance the light detection capability.

3. The BeZnOS quaternary ZnO alloy semiconductor material of the present invention can be grown by conventional pulsed laser ablation deposition, magnetron sputtering, electron beam evaporation and other methods, and the electrode material can be made of metal aluminum, gold, silver, etc. And the channel width can be freely adjusted and optimized. The electrode of the present invention can be fabricated by either vapor deposition or photolithography. The evaporation method has a simple process and is convenient for large-scale preparation; the photolithography method is very beneficial to the development of high-precision and micro-sized devices.

4. The ultraviolet light detector of the MSM structure prepared by the present invention has a simple structure, a simple manufacturing process, and low cost of raw materials. In addition, the detector prepared by the present invention has a good detection ability for ultraviolet light with a wavelength of 300 nm, and has a fast response speed, Small dark current and stable performance.

Description of drawings

Fig. 1 is the structural representation of the spontaneous polarization field-enhanced ultraviolet light detector based on BeZnOS quaternary alloy of the present invention;

Fig. 2 is the I-V curve of the spontaneous polarization enhanced photodetector prepared in Example 1 of the present invention;

3 is a response rate diagram of a spontaneous polarization enhanced photodetector prepared in Example 1 of the present invention;

Fig. 4 is the I-V curve of the spontaneous polarization enhanced photodetector prepared in Example 2 of the present invention;

5 is a response rate diagram of a spontaneous polarization enhanced photodetector prepared in Example 2 of the present invention;

6 is the I-V curve of the self-polarization-free enhanced photodetector prepared in Example 3 of the present invention;

7 is a response rate diagram of a self-polarization-free enhanced photodetector prepared in Example 3 of the present invention;

FIG. 8 is the spectral responsivity test result of the spontaneous polarization enhanced photodetector prepared in Example 2 of the present invention.

Detailed ways

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. This embodiment case is implemented on the premise of the technical solution of the present invention, and provides a detailed implementation manner and a specific operation process, but the protection scope of the present invention is not limited to the following embodiment cases.

From the information contained in this application, various changes to the precise description of the present invention can be readily made by those skilled in the art without departing from the spirit and scope of the appended claims. It is to be understood that the scope of the invention is not limited to the processes, properties or components defined, as these embodiments and other descriptions are intended to be illustrative only of particular aspects of the invention. Indeed, various modifications of the embodiments of the invention that are obvious to those skilled in the art or related fields are intended to be within the scope of the appended claims.

For a better understanding of the invention and not to limit the scope of the invention, all numbers expressing amounts, percentages, and other numerical values used in this application should in all cases be understood as modified by the word "about". Accordingly, unless expressly stated otherwise, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained. At a minimum, each numerical parameter shall be deemed to have been obtained from the reported significant digits and by conventional rounding methods.

The main component of the sapphire substrate used in the following embodiments of the present invention is aluminum oxide (Al ₂ O ₃ ), and m-Al ₂ O ₃ represents m-plane sapphire. In the present invention, the thickness of the sapphire substrate is preferably 0.35 to 0.45 mm.

Example 1

As shown in FIG. 1 , a spontaneous polarization field-enhanced ultraviolet light detector based on BeZnOS quaternary alloy in this embodiment, the detector includes an m-plane sapphire substrate, an active layer, a pair of A parallel metal Al electrode, wherein: the active layer is an m-plane BeZnOS quaternary alloy thin film, and the parallel metal electrode is perpendicular to the c-axis direction of the BeZnOS quaternary alloy thin film. The thickness of the substrate is 0.43 mm, the thickness of the active layer is 120 nm, the thickness of the Al electrode is 50 nm, and the distance between the parallel electrodes is 10 μm.

The above-mentioned spontaneous polarization field-enhanced ultraviolet light detector based on BeZnOS quaternary alloy in this embodiment is prepared by the following method, including the following steps:

Step 1: Preparation of BeZnOS quaternary ceramic target by solid-phase sintering

1.1 Molar ratio ZnS:BeO=95:5, weigh 55.558g ZnS powder and 7.504g BeO powder, after mixing, add 39g deionized water, and then place it in the ball mill tank in the planetary ball mill (the ball milling medium is zirconia ceramics) ball), ball milled for 4h to obtain mixed powder;

1.2 Put the mixed powder in a vacuum drying box, dry it in a vacuum at 110°C for 10 hours, take it out and cool it to room temperature naturally, sieve off the zirconia balls, add 6g of ethanol, fully grind with a grinding bowl and use a tablet press Pressed into a circular blank with a diameter of 27.5mm and a thickness of 2mm under a pressure of 10M Pa;

1.3 Put the green sheet in a crucible in a vacuum tube furnace, and put powder (15.0000g) and high-purity sulfur powder (3.3000g) with the same composition around it. The vacuum tube furnace was evacuated to 0.1Pa, and then high-purity argon was introduced, and the procedure was repeated 3 times. The tube furnace is heated to 1300° C. and kept for 2 hours under a protective atmosphere, and then naturally cooled to room temperature to obtain the BeZnOS quaternary ceramic target of the present invention.

Step 2: Fabrication of UV Light Detectors Using BeZnOS Quaternary Ceramic Targets

2.1 Use the BeZnOS quaternary ceramic target prepared in step 1 as the laser ablation target, and put it into the vacuum chamber together with the substrates that have been ultrasonically cleaned with acetone, anhydrous ethanol and deionized water for 15 min respectively, and evacuated to 10 ^-4 Pa;

2.2 Turn on the substrate heating and adjust the substrate temperature to 700°C, and inject oxygen to keep the air pressure at 2Pa during the entire film deposition process; then turn on the substrate and the target table to rotate, set the laser output energy to 400mJ/pulse, and the pulse The repetition frequency is 5 Hz, and the laser deposition is turned on for 30 min, then the oxygen and substrate heating are turned off, and finally the sample is naturally cooled to room temperature in vacuum and taken out from the vacuum chamber;

2.3 Determine the c-axis direction of the film by XRD scanning, and mark the back of the sample. Install the film and mask into the vacuum chamber of the vacuum evaporation machine, so that the electrode channel is perpendicular to the c-axis of the sample, install the tungsten boat and put it into the evaporation source - metal aluminum 0.2g, close the vacuum chamber, turn on the mechanical pump, the front stage Valve and molecular pump to pump the vacuum to 10 ^-4 Pa. After reaching the vacuum degree, turn on the evaporation power supply, keep the temperature at 400 °C for 2 minutes, slowly increase the current until the metal aluminum melts and keep the current constant, open the baffle to slowly reduce the current after the metal evaporation is completed, close the evaporation source, and turn off the molecular pump. , backstage valve, mechanical pump, and open the air valve to get the target MSM UV detector.

A voltage of 10V was applied between the electrodes of the device prepared in this example to conduct photoelectric tests. The results show that the device has obvious detection ability and fast response speed for ultraviolet light. The fast response times τ _r1 and τ _d1 of the device are 0.28s and 0.11s, respectively, and the test results are shown in Figure 2 and Figure 3, respectively.

Example 2

A spontaneous polarization field-enhanced ultraviolet light detector based on a BeZnOS quaternary alloy in this embodiment, the detector includes an m-plane sapphire substrate, an active layer, and a pair of parallel metal Al electrodes in sequence from bottom to top, wherein : the active layer is an m-plane BeZnOS quaternary alloy thin film, and the parallel metal electrodes are perpendicular to the c-axis direction of the BeZnOS quaternary alloy thin film. The thickness of the substrate is 0.43 mm, the thickness of the active layer is 90 nm, the thickness of the electrodes is 55 nm, and the distance between the parallel electrodes is 10 μm.

The above-mentioned spontaneous polarization field-enhanced ultraviolet light detector based on BeZnOS quaternary alloy in this embodiment is prepared by the following method, including the following steps:

Step 1: Preparation of BeZnOS quaternary ceramic target by solid-phase sintering

1.1 Molar ratio ZnS:BeO=85:15, weigh 49.710g of ZnS powder and 22.511g of BeO powder, after mixing, add 36g of deionized water, and then place it in the ball milling tank of the planetary ball mill (the ball milling medium is zirconia ceramics) ball), ball milled for 4h to obtain mixed powder;

1.2 Put the mixed powder in a vacuum drying box, dry it in a vacuum at 110°C for 10 hours, take it out and cool it to room temperature naturally, sieve off the zirconia balls, add 6g of ethanol, fully grind with a grinding bowl and use a tablet press Pressed into a circular blank with a diameter of 27.5mm and a thickness of 2mm under a pressure of 10M Pa;

1.3 Put the green sheet in a crucible in a vacuum tube furnace, and put powder (15.0000g) and high-purity sulfur powder (3.3000g) with the same composition around it. The vacuum tube furnace was evacuated to 0.1Pa, and then high-purity argon was introduced, and the procedure was repeated 3 times. The tube furnace is heated to 1200° C. and kept for 5 hours under a protective atmosphere, and then naturally cooled to room temperature to obtain the BeZnOS quaternary ceramic target of the present invention.

Step 2: Fabrication of UV Light Detectors Using BeZnOS Quaternary Ceramic Targets

2.1 Use the BeZnOS quaternary ceramic target prepared in step 1 as the laser ablation target, and put it into the vacuum chamber together with the substrates that have been ultrasonically cleaned with acetone, anhydrous ethanol and deionized water for 15 min respectively, and evacuated to 10 ^-4 Pa;

2.2 Turn on the substrate heating and adjust the substrate temperature to 400°C, and inject oxygen to keep the air pressure at 4Pa during the entire film deposition process; then turn on the substrate and the target table to rotate, set the laser output energy to 250mJ/pulse, and the pulse The repetition frequency was 5 Hz, and the laser deposition was turned on for 60 min, then the oxygen and the substrate heating were turned off, and finally the sample was naturally cooled to room temperature in vacuum and taken out from the vacuum chamber;

2.3 The sample obtained in step 2 was scanned by XRD to determine the c-axis direction of the film, and marked on the back of the sample. Mount the thin film and interdigital electrode mask into the vacuum chamber of the vacuum evaporation machine so that the electrode channel is perpendicular to the c-axis of the sample. Install the tungsten boat, put in the evaporation source—metal aluminum 0.2g, close the vacuum chamber, open the mechanical pump, the front valve, and the molecular pump, and pump the vacuum to 10 ^{- 4} Pa. After reaching the vacuum degree, turn on the evaporation power supply, increase the current at a speed of 100A/min until the metal aluminum melts, open the baffle to slowly reduce the current after the metal evaporation is completed, close the evaporation source, close the molecular pump, the front valve, and the mechanical pump. Open the air valve. Remove the sample after turning off the instrument.

A voltage of 10V was applied between the electrodes of the device prepared in this example to conduct photoelectric tests. The results show that the device has obvious detection ability and fast response speed for ultraviolet light. The fast response time τ _r1 and τ _d1 of the device are 0.19s and 0.21s, respectively, and the response band is in the ultraviolet region. The test results are shown in Figure 4, Figure 5 and Figure 8, respectively.

Example 3 (comparative example)

A non-spontaneous polarization field-enhanced ultraviolet light detector based on a BeZnOS quaternary alloy in this embodiment, the detector includes an m-plane sapphire substrate, an active layer, and a pair of parallel metal Al electrodes in sequence from bottom to top, Wherein: the active layer is an m-plane BeZnOS quaternary alloy thin film, and the parallel metal electrodes are parallel to the c-axis direction of the BeZnOS quaternary alloy thin film. The thickness of the substrate is 0.43 mm, the thickness of the active layer is 90 nm, the thickness of the electrodes is 60 nm, and the distance between the parallel electrodes is 10 μm.

The above-mentioned BeZnOS quaternary alloy-based ultraviolet light detector without spontaneous polarization is prepared by the following method, including the following steps:

Step 1: Preparation of BeZnOS quaternary ceramic target by solid-phase sintering

1.1 Molar ratio ZnS:BeO=92:8, weigh 53.803g of ZnS powder and 18.065g of BeO powder, after mixing, add 39g of deionized water, and then place it in the ball milling tank of the planetary ball mill (the ball milling medium is zirconia ceramics) ball), ball milled for 4h to obtain mixed powder;

1.2 Put the mixed powder in a vacuum drying box, dry it in a vacuum at 110°C for 10 hours, take it out and cool it to room temperature naturally, sieve off the zirconia balls, add 6g of ethanol, fully grind with a grinding bowl and use a tablet press Pressed into a circular blank with a diameter of 27.5mm and a thickness of 2mm under a pressure of 10M Pa;

1.3 Put the green sheet in a crucible in a vacuum tube furnace, and put powder (15.0000g) and high-purity sulfur powder (3.3000g) with the same composition around it. The vacuum tube furnace was evacuated to 0.1Pa, and then high-purity argon was introduced, and the procedure was repeated 3 times. The tube furnace is heated to 1300° C. and kept for 2 hours under a protective atmosphere, and then naturally cooled to room temperature to obtain the BeZnOS quaternary ceramic target of the present invention.

Step 2 Preparation of UV light detector using BeZnOS quaternary ceramic target

2.1 Use the BeZnOS quaternary ceramic target prepared in step 1 as the laser ablation target, and put it into the vacuum chamber together with the substrates that have been ultrasonically cleaned with acetone, anhydrous ethanol and deionized water for 15 min respectively, and evacuated to 10 ^-4 Pa;

2.2 Turn on the substrate heating and adjust the substrate temperature to 400 °C, and inject oxygen to keep the air pressure at 4Pa during the entire film deposition process; then turn on the substrate and the target table to rotate, set the laser output energy to 400mJ/pulse, pulse The repetition frequency is 5Hz, the number of pulses is 9000, and the laser deposition is turned on for 30 minutes, then the oxygen and substrate heating are turned off, and finally the sample is naturally cooled to room temperature in vacuum and taken out from the vacuum chamber;

2.3 Scan the (103) plane of the sample obtained in step 2 using four-circle single crystal XRD to determine the c-direction of the sample and mark it. Install the sample and mask so that the electrode is parallel to the c-axis, install the tungsten boat and put in the evaporation source - metal aluminum 0.3g, close the vacuum chamber, open the mechanical pump, front valve, and molecular pump, and pump the vacuum to 10 ^-4 Pa. After reaching the vacuum degree, turn on the evaporation power supply, increase the current at a speed of 100A/min until the metal aluminum melts, open the baffle to slowly reduce the current after the metal evaporation is completed, close the evaporation source, close the molecular pump, the front valve, and the mechanical pump. , and open the air valve. When the vacuum chamber is filled with air, the instrument is turned off, the sample is taken out, and the target photodetector is obtained.

A voltage of 10V was applied between the electrodes of the device prepared in this example to conduct photoelectric tests. The results show that the device has a slower response speed to ultraviolet light than the spontaneous polarization field-enhanced detector. The device's fast response times τ _r1 and τ _d1 are 0.30s and 0.46s, respectively, and the test results are shown in Figure 6 and Figure 7, respectively.

Example 4

A spontaneous polarization field-enhanced ultraviolet light detector based on BeZnOS quaternary alloy in this embodiment, the detector includes an m-plane sapphire substrate, an active layer, and a pair of parallel metal Au electrodes in sequence from bottom to top, wherein : the active layer is an m-plane BeZnOS quaternary alloy thin film, and the parallel metal electrodes are perpendicular to the c-axis direction of the BeZnOS quaternary alloy thin film. The thickness of the substrate is 0.43 mm, the thickness of the active layer is 80 nm, the thickness of the electrodes is 30 nm, and the distance between the parallel electrodes is 30 μm.

The above-mentioned spontaneous polarization field-enhanced ultraviolet light detector based on BeZnOS quaternary alloy in this embodiment is prepared by the following method, including the following steps:

Step 1: The BeZnOS quaternary ceramic target was prepared by the same solid-phase sintering method as in Example 1.

Step 2 Preparation of UV light detector using BeZnOS quaternary ceramic target

2.1 Use the BeZnOS quaternary ceramic target prepared in step 1 as the laser ablation target, and put it into the vacuum chamber together with the substrates that have been ultrasonically cleaned with acetone, anhydrous ethanol and deionized water for 15 min respectively, and evacuated to 10 ^-4 Pa;

2.2 Turn on the substrate heating and adjust the substrate temperature to 100°C, inject oxygen, so that the air pressure is maintained at 8Pa during the entire film deposition process; then turn on the substrate and the target table to rotate, set the laser output energy to 200mJ/pulse, pulse The repetition frequency was 5 Hz, and then the laser deposition was turned on for 10 min, then the oxygen and the substrate heating were turned off, and finally the sample was naturally cooled to room temperature in vacuum and taken out from the vacuum chamber;

2.3 Determine the c-axis direction of the film by XRD scanning, and mark the back of the sample. Install the film and mask into the vacuum chamber of the vacuum evaporation machine, make the electrode channel perpendicular to the c-axis of the sample, install the tungsten boat and put it into the evaporation source - metal Au0.2g, close the vacuum chamber, turn on the mechanical pump, the front stage Valve and molecular pump to pump the vacuum to 10 ^-4 Pa. After reaching the vacuum degree, turn on the evaporation power supply, keep it at 400 °C for 2 minutes, slowly increase the current until the metal Au melts and keep the current constant, open the baffle to slowly reduce the current after the metal evaporation is completed, turn off the evaporation source, and turn off the molecular pump. , the foreline valve, the mechanical pump, and the open air valve to get the target MSM UV detector.

Example 5

A spontaneous polarization field-enhanced ultraviolet light detector based on BeZnOS quaternary alloy in this embodiment, the detector includes an m-plane sapphire substrate, an active layer, and a pair of parallel metal Pt electrodes in sequence from bottom to top, wherein : the active layer is an m-plane BeZnOS quaternary alloy thin film, and the parallel metal electrodes are perpendicular to the c-axis direction of the BeZnOS quaternary alloy thin film. The thickness of the substrate is 0.43 mm, the thickness of the active layer is 160 nm, the thickness of the electrodes is 30 nm, and the distance between the parallel electrodes is 60 μm.

The spontaneous polarization field-enhanced ultraviolet light detector based on the BeZnOS quaternary alloy described above in this embodiment is prepared by the following method, including the following steps:

Step 1: The BeZnOS quaternary ceramic target was prepared by the same solid-phase sintering method as in Example 1.

Step 2 Preparation of UV light detector using BeZnOS quaternary ceramic target

2.1 Use the BeZnOS quaternary ceramic target prepared in step 1 as the laser ablation target, and put it into the vacuum chamber together with the substrates that have been ultrasonically cleaned with acetone, anhydrous ethanol and deionized water for 15 min respectively, and evacuated to 10 ^-4 Pa;

2.2 Turn on the substrate heating and adjust the substrate temperature to 800°C, and inject oxygen to keep the air pressure at 10Pa during the entire film deposition process; then turn on the substrate and the target table to rotate, set the laser output energy to 600mJ/pulse, pulse The repetition frequency is 5 Hz, and the laser deposition is turned on for 40 minutes, then the oxygen and substrate heating are turned off, and finally the sample is naturally cooled to room temperature in vacuum and taken out from the vacuum chamber;

2.3 Determine the c-axis direction of the film by XRD scanning, and mark the back of the sample. Install the film and mask into the vacuum chamber of the vacuum evaporation machine, so that the electrode channel is perpendicular to the c-axis of the sample, install the tungsten boat and put it into the evaporation source - metal Ag0.2g, close the vacuum chamber, turn on the mechanical pump, the front stage Valve and molecular pump to pump the vacuum to 10 ^-4 Pa. After reaching the vacuum degree, turn on the evaporation power supply, keep it at 400 °C for 2 minutes, slowly increase the current until the metal Ag is melted and keep the current constant, open the baffle to slowly reduce the current after the metal is evaporated, turn off the evaporation source, and turn off the molecular pump. , the foreline valve, the mechanical pump, and the open air valve to get the target MSM UV detector.

Claims (9)

1. a spontaneous polarization field-enhanced ultraviolet light detector based on BeZnOS quaternary alloy, is characterized in that: described detector comprises m-plane sapphire substrate, active layer, a pair of parallel metal electrodes successively from bottom to top, Wherein: the active layer is an m-plane BeZnOS quaternary alloy thin film, and the parallel metal electrodes are perpendicular to the c-axis direction of the BeZnOS quaternary alloy thin film. 2 . The spontaneous polarization field-enhanced ultraviolet light detector based on BeZnOS quaternary alloy according to claim 1 , wherein the thickness of the m-plane sapphire substrate is 0.35-0.45 mm. 3 . 3 . The spontaneously polarized field-enhanced ultraviolet light detector based on BeZnOS quaternary alloy according to claim 1 , wherein the thickness of the active layer is 80-160 nm. 4 . 4 . The spontaneously polarized field-enhanced ultraviolet light detector based on BeZnOS quaternary alloy according to claim 1 , wherein the thickness of the parallel metal electrodes is 30-60 nm. 5 . 5 . The spontaneously polarized field-enhanced ultraviolet light detector based on BeZnOS quaternary alloy according to claim 1 , wherein the distance between the parallel metal electrodes is 10-100 μm. 6 . 6 . The spontaneously polarized field-enhanced ultraviolet light detector based on BeZnOS quaternary alloy according to claim 1 , wherein the parallel metal electrode material can be any one of Au, Ag or Al. 7 . 7. the preparation method of the spontaneous polarization field-enhanced ultraviolet light detector based on BeZnOS quaternary alloy according to claim 1, is characterized in that: described method comprises the following steps: (1) take m-plane sapphire as the substrate of thin film growth, utilize cleaning liquid to carry out ultrasonic cleaning to described substrate, dry with nitrogen gas, place in the vacuum chamber of pulsed laser deposition system immediately; (2) depositing an m-plane BeZnOS quaternary alloy film on the surface of the pre-treated m-plane sapphire substrate in step (1) by using pulsed laser ablation deposition, magnetron sputtering or electron beam evaporation; (3) determining the c-axis direction of the m-plane BeZnOS quaternary alloy thin film obtained in step (2) by using a four-circle single crystal X-ray diffractometer; (4) Using evaporation method or photolithography method, a pair of parallel metal electrodes are formed on the surface of the BeZnOS quaternary alloy film in the vertical direction of the c-axis to obtain the spontaneous polarization field enhanced type of BeZnOS quaternary alloy according to the present invention UV light detector. 8. the preparation method of the spontaneous polarization field-enhanced ultraviolet light detector based on BeZnOS quaternary alloy according to claim 7, is characterized in that: in step (2), m-plane BeZnOS quaternary alloy thin film specifically adopts pulsed laser The ablation deposition method is obtained, and the specific process is as follows: Using BeZnOS ceramics as the target, the substrate temperature is controlled to be 100-800°C, the pulse laser energy is 200-600mJ/Pulse, and the oxygen pressure is 0-10Pa, and the pre-treated m-plane sapphire substrate is deposited on the surface of the step (1). A BeZnOS quaternary alloy thin film is formed. 9. the preparation method of the spontaneous polarization field-enhanced ultraviolet light detector based on BeZnOS quaternary alloy according to claim 8, is characterized in that: described BeZnOS ceramic target material adopts solid phase sintering method to make, and concrete method is as follows : (a) Mix the ZnS and BeO powders evenly in a molar ratio of 99:1 to 70:30, add ultrapure water, mix them evenly again, and then place them in a ball mill for ball milling to obtain a mixed powder; (b) drying the mixed powder in a vacuum drying oven and cooling to room temperature, then crushing and pressing into a disc; (c) in an argon atmosphere, using sulfur powder as an oxygen scavenger, the wafer obtained in step (b) is placed in a vacuum tube furnace, and fired at 1100-1400 ° C for 2-5 hours to obtain the invention described in the present invention. BeZnOS ceramics.

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