Preparation method of ultra-wide bandgap semiconductor and application of ultra-wide bandgap semiconductor in heterojunction deep ultraviolet photoelectric detector

Abstract

The invention belongs to the technical field of deep ultraviolet photoelectric detectors, and particularly relates to a preparation method of an ultra-wide bandgap semiconductor and application of the ultra-wide bandgap semiconductor in a heterojunction deep ultraviolet photoelectric detector. The ultra-wide forbidden band semiconductor film (Ga2O3) obtained by the preparation method has a high band gap value (4.4-5.3 eV), good stability and relatively high breakdown voltage, and the corresponding wave band of the ultra-wide forbidden band semiconductor film is a deep ultraviolet (UVC) range of 200-280 nm. Moreover, the device is almost free of any response when placed in the sun, and almost free of external interference on the response of a deep ultraviolet light source. The heterojunction deep ultraviolet photoelectric detector prepared by the method can show excellent performance and relatively good repeatability stability under the irradiation of 254nm ultraviolet light, has a self-driving function, and can realize light detection without external voltage.

Description

Technical Field

[0001] The invention belongs to the technical field of deep ultraviolet photoelectric detectors, and in particular relates to a method for preparing an ultra-wide bandgap semiconductor and an application of the same in a heterojunction deep ultraviolet photoelectric detector. Background Art

[0002] With the development of electronic information technology, deep ultraviolet photodetectors have become a research hotspot due to their absorption characteristics by the atmospheric ozone layer. In addition, deep ultraviolet photodetectors also have broad application prospects in flame detection, corona detection, environmental detection, etc.

[0003] Ga 2 O 3 Compared with GaN, SiC, Ga 2 O 3 Compared with ZnO, it has a larger band gap (4.4-5.3eV), good stability, high breakdown voltage, excellent radiation hardness and other advantages, thus showing great application potential in solar-blind areas. 2 O 3 The method of producing metal oxides is relatively simple and does not require complicated chemical processes. These advantages make Ga 2 O 3 It has become the preferred research direction for solar-blind ultraviolet photodetectors; but Ga 2 O 3 As a new type of ultra-wide bandgap semiconductor, its preparation and application in the field of photodetector technology still require more exploration and research. Summary of the invention

[0004] To this end, the present application provides an ultra-wide bandgap semiconductor (Ga 2 O 3 ) and its application in heterojunction deep ultraviolet photodetectors, aiming to effectively improve the performance and sensitivity of deep ultraviolet photodetectors.

[0005] To this end, the first technical solution of the present application discloses a method for preparing an ultra-wide bandgap semiconductor, comprising calcining a P-type gallium nitride substrate under oxygen-permeable conditions.

[0006] Preferably, the calcination temperature is 900-1000° C., and the calcination time is 20 min-2 h.

[0007] And, the ultra-wide bandgap semiconductor prepared according to the above preparation method. The ultra-wide bandgap semiconductor obtained in this application is Ga 2 O 3 , which exists in the form of ultra-wide bandgap semiconductor films.

[0008] The second technical solution of the present application discloses the application of the above ultra-wide bandgap semiconductor in the preparation of a heterojunction deep ultraviolet photodetector. It is generally prepared into a heterojunction deep ultraviolet photodetector for detecting deep ultraviolet light.

[0009] The third technical solution of the present application discloses a method for preparing a heterojunction deep ultraviolet photodetector, comprising the following steps:

[0010] The ultra-wide bandgap semiconductor is subjected to photoresist lithography and phosphoric acid solution etching to obtain a heterojunction of gallium nitride and potassium oxide;

[0011] A mask is attached to the heterojunction, and after electrode plating, a heterojunction deep ultraviolet photodetector is obtained.

[0012] Furthermore, the photolithography step is specifically to coat the ultra-wide bandgap semiconductor with photoresist, bake at 95° C.-100° C. for 90s-120s, expose for 6s, develop for 40s-60s, and then blow dry with a nitrogen gun.

[0013] Furthermore, the etching temperature is 160°C-200°C.

[0014] Preferably, the electrode is a Ti / Pt / Au electrode.

[0015] Also, a heterojunction deep ultraviolet photodetector prepared according to the above preparation method and its application in detecting deep ultraviolet light.

[0016] Beneficial effects of the present invention:

[0017] 1. The ultra-wide bandgap semiconductor film (Ga 2 O 3 ) has a high band gap value (4.4-5.3eV), good stability, and a high breakdown voltage, and its corresponding band is the deep ultraviolet range (UVC) of 200-280nm. Since most of the deep ultraviolet light is absorbed by the atmosphere when it enters the earth's surface, there is basically no ultraviolet light of 200-280nm in the natural light on the surface, so it can be used as a photodetector in the solar-blind range.

[0018] 2. The ultra-wide bandgap semiconductor film provided by the present invention has almost no response when placed in sunlight, and there is almost no external interference in the response to the deep ultraviolet light source.

[0019] 3. The heterojunction deep ultraviolet photodetector provided by the present invention can exhibit excellent performance and good repeatability stability under 254nm ultraviolet light.

[0020] 4. The present invention utilizes thermal oxidation method to prepare heterojunction deep ultraviolet photodetector, which simplifies the thin film preparation process.

[0021] 5. The heterojunction deep ultraviolet photodetector prepared by the present invention has a self-driving function and can detect light without the need for an external voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is the XRD pattern of the ultra-wide bandgap semiconductor of Example 1;

[0023] Figure 2 This is the XPS graph of the ultra-wide bandgap semiconductor of Example 1;

[0024] Figure 3 This is an EDS image of the ultra-wide bandgap semiconductor of Example 1;

[0025] Figure 4 is a SEM cross-sectional view of the ultra-wide bandgap semiconductor of Example 1;

[0026] Figure 5 is the IV curve of the photodetector of Example 2;

[0027] Figure 6 Graph showing performance parameters of the photodetector of Example 2 under a -2V bias voltage;

[0028] Figure 7 Graph showing performance index parameters of the photodetector of Example 2 under 0V bias voltage;

[0029] Figure 8 IV curves of different light intensities of the photodetector in Example 2;

[0030] Fig. 9 is an IT stability diagram of the photodetector of Example 2;

[0031] Fig.10 Graph showing the response time of a single cycle of the photodetector of Example 2. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so that once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0034] The experimental methods in the following examples are all conventional methods unless otherwise specified. The experimental materials used in the following examples were all purchased from commercial channels, and quality control measures were introduced into the experimental process to ensure the quality of the data results.

[0035] The first embodiment of the present application discloses a method for preparing an ultra-wide bandgap semiconductor, comprising calcining a P-type gallium nitride substrate under oxygen-permeable conditions; the calcination temperature is 900-1000° C., and the calcination time is 20 min-2 h.

[0036] And, the ultra-wide bandgap semiconductor prepared according to the above preparation method. The ultra-wide bandgap semiconductor obtained in this application is Ga 2 O 3 , which exists in the form of ultra-wide bandgap semiconductor films.

[0037] It can be understood that in this embodiment, the P-type gallium nitride substrate further includes steps such as cleaning before calcination. Preferably, the substrate is sequentially placed in propanol, isopropanol, and deionized water for cleaning, and then blown dry with nitrogen to remove surface impurities.

[0038] In some preferred embodiments, the calcination is carried out in a tube furnace, and after the calcination is completed, the temperature is naturally cooled to room temperature to obtain an ultra-wide bandgap semiconductor film grown on the substrate, namely, Ga 2 O 3 .

[0039] In this embodiment, the substrate is P-type gallium nitride, preferably P-type gallium nitride epitaxially grown on sapphire, obtained by thermal oxidation (oxygen calcination). 2 O 3Thin films using magnetron sputtering (RF), molecular beam epitaxy (MBE), atomic layer deposition (ALD), metal organic chemical vapor deposition (MOCVD) and other technologies require the use of expensive instruments and gallium source materials. This application only requires a tube furnace and a high-purity oxygen bottle to grow β-Ga 2 O 3 , greatly reducing costs.

[0040] The second embodiment of the present application discloses the application of the above-mentioned ultra-wide bandgap semiconductor in the preparation of a heterojunction deep ultraviolet photodetector. 2 O 3 )The band gap value is 4.4-5.3eV, corresponding to the deep ultraviolet range of 200-280nm, and there is almost no response when placed in the sun, and there is almost no external interference in the response to the deep ultraviolet light source. Therefore, it is applied to the preparation of heterojunction deep ultraviolet photodetectors, which can show excellent repeatability and stability under 254nm ultraviolet light.

[0041] The third embodiment of the present application discloses a method for preparing a heterojunction deep ultraviolet photodetector, comprising the following steps:

[0042] The ultra-wide bandgap semiconductor is subjected to photoresist lithography and phosphoric acid solution etching to obtain a heterojunction of gallium nitride and potassium oxide;

[0043] A mask is attached to the heterojunction, and after electrode plating, a heterojunction deep ultraviolet photodetector is obtained.

[0044] It should be noted that, in this embodiment, after etching with phosphoric acid solution, gallium is partially oxidized and gallium nitride is exposed. Since gallium oxide and gallium nitride are two different semiconductor materials with different energy band gaps and conductivity types, a heterojunction will be formed in the interface region formed by the contact between the two semiconductors.

[0045] In some specific embodiments, the photolithography step is specifically to coat the ultra-wide bandgap semiconductor with photoresist, bake at 95°C-100°C for 90s-120s, expose for 6s, develop for 40s-60s, and then blow dry with a nitrogen gun. Preferably, the coating is carried out in a spin coater.

[0046] In some specific embodiments, the etching temperature is 160° C.-200° C., the etching time is 2 min, and after the etching is completed, the etching is rinsed with deionized water and then dried with nitrogen.

[0047] It can be understood that the heterojunction after etching also includes a process of removing the photoresist by soaking in acetone before electrode plating. After removal, it is washed with isopropanol and deionized water in sequence to obtain a heterojunction of gallium nitride and gallium oxide.

[0048] Preferably, the electrode is a Ti / Pt / Au electrode.

[0049] This embodiment adopts thermal oxidation method to prepare heterojunction deep ultraviolet photodetector, which simplifies the thin film preparation process compared with the prior art. For example, when using PLD to grow gallium oxide, it is necessary to consider a variety of growth parameters, mainly substrate temperature, laser energy, background pressure, laser frequency, etc. In order to grow high-quality gallium oxide thin films, a lot of experimental exploration is required. The thermal oxidation method of this application grows gallium oxide, which has a simple process, few parameters to consider, and can grow high-quality gallium oxide thin films, which have good performance in optoelectronic devices.

[0050] It can be understood that by plating Ti / Pt / Au electrodes on the outside of the heterojunction, the heterojunction deep ultraviolet photodetector prepared in the present application has a self-driving function and can detect light without the need for an external voltage.

[0051] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0052] Example 1 Preparation of Ultra-Wide Bandgap Semiconductor

[0053] S1. The P-type gallium nitride substrate was sequentially placed in acetone, isopropanol, and deionized water and cleaned in an ultrasonic cleaner for 20 minutes, and then dried with nitrogen to obtain a pretreated substrate;

[0054] S2. Place the pretreated substrate into a tube furnace, calcine it at 1000°C for 40 minutes with oxygen, and take it out after the tube furnace cools down to room temperature to obtain the Ga grown on the P-type gallium nitride substrate. 2 O 3 Thin film, that is, ultra-wide bandgap semiconductor.

[0055] Example 2 Preparation of Ultra-Wide Bandgap Semiconductor

[0056] S1. The P-type gallium nitride substrate was sequentially placed in acetone, isopropanol, and deionized water and cleaned in an ultrasonic cleaner for 20 minutes, and then dried with nitrogen to obtain a pretreated substrate;

[0057] S2. Place the pretreated substrate in a tube furnace, calcine it at 1000°C for 60 minutes with oxygen, and take it out after the tube furnace cools down to room temperature to obtain the Ga grown on the P-type gallium nitride substrate. 2 O 3 Thin film, that is, ultra-wide bandgap semiconductor.

[0058] like Figure 1 The XRD pattern of the ultra-wide bandgap semiconductor obtained in Example 1 is shown as follows: Figure 1The figure shows the XRD patterns of the original GaN substrate (P-type gallium nitride substrate) and the semiconductors of Example 1 (calcined for 40 min) and Example 2 (calcined for 60 min). 2 O 3 There are five isomers: α, β, γ, δ, ε, among which β-Ga is the most stable. 2 O 3 When the growth temperature exceeds 800°C, all other isomers are converted to β-isomers. From the figure, it can be seen that compared with the original GaN substrate, diffraction peaks of (-201), (-402), and (-603) appear at 18.75°, 38.21°, and 58.88°, corresponding to β-Ga 2 O 3 , which is a monoclinic structure. Therefore, β-Ga can be successfully grown by thermal oxidation. 2 O 3 film.

[0059] like Figure 2 The XPS graph of the ultra-wide bandgap semiconductor obtained in Example 1 is shown as follows: Figure 3 The EDS graph of the ultra-wide bandgap semiconductor obtained in Example 1 is shown. It can be seen from the figure that Ga 3+ The peak area is the largest, reflecting that the ultra-wide bandgap semiconductor prepared in Example 1 is Ga 2 O 3 Form exists.

[0060] like Figure 4 The upper surface image (SEM cross-sectional image) of the ultra-wide bandgap semiconductor film prepared in Example 1 is shown. It can be seen from the figure that the surface of the film is composed of blocky particles connected together, and the film is continuous and dense. It can be clearly seen in the figure that after calcination for 40 minutes, Ga 2 O 3 The film layer is about 200nm and dense.

[0061] Example 3 Preparation of Heterojunction Deep Ultraviolet Photodetector

[0062] S1. Place the ultra-wide bandgap semiconductor into a spin coater, add two drops of photoresist and apply, bake at 95°C for 90 seconds, expose for 6 seconds, take it out and develop for 40 seconds, and finally blow dry with a nitrogen gun;

[0063] S2. Place the semiconductor after photolithography in a phosphoric acid solution and etch it at 160°C. After two minutes, take out the substrate and rinse it with deionized water, and then blow it dry with a nitrogen gun;

[0064] S3. Soak the etched semiconductor in acetone for one day to remove the photoresist; then wash it with acetone, isopropanol, and deionized water in sequence to finally obtain a heterojunction of gallium nitride and gallium oxide;

[0065] S4. A mask is attached to the processed semiconductor, and Ti / Pt / Au electrodes are plated by magnetron sputtering to obtain the heterojunction deep ultraviolet photodetector.

[0066] like Figure 5 The IV curve of the photodetector described in Example 3 is shown; Figure 8 is the IV curve of the photodetector of Example 3 at different light intensities, Figure 6 The performance parameter diagram of the photodetector of Example 2 under -2V bias voltage is shown in FIG. Figure 5 It can be seen that the heterojunction deep ultraviolet photodetector prepared in Example 2 has a low dark current at a bias voltage of -2 V, with a value of 3.81×10 -12 A, at -2V bias, wavelength 254nm, light intensity 50μW / cm 2 Under ultraviolet light, the photocurrent reaches 1.45×10 -6 A, such as Figure 6 As shown in Figure 2, its light-to-dark current ratio (PDCR) can reach 2.658×10 5 , the responsivity R is 0.969A / W, the detection rate D * 1.27×10 14 Jones, showing good performance. And it has photoelectric performance under different light intensities, and also has high responsivity R and detection rate D under low light intensity * , indicating that the device also responds to weak light intensities.

[0067] Figure 7 The performance index parameter diagram of the photodetector of Example 3 under 0V bias voltage; as shown in the figure: the heterojunction deep ultraviolet photodetector of the present invention also has a high detection rate D under 0V bias voltage, wavelength of 254nm and different light intensities. * And the responsivity R. At a light intensity of 50μW / cm 2 Under these conditions, the detection rate D * The highest value can reach 1.83×10 11 , indicating that it has good self-driving performance under 0V bias.

[0068] Fig. 9 This is the IT stability diagram of the photodetector in Example 2. The heterojunction deep ultraviolet photodetector provided in the embodiment of the present invention has very stable performance within 1200 seconds and basically no attenuation under long-term illumination, which shows that the device has good stability and repeatability.

[0069] Fig.10 is a single cycle response time curve of the photodetector of Example 2. The τ of the device provided in the embodiment of the present invention is rise and τ decay The response time is 0.045s and 0.0729s respectively, which is faster than the response time reported in most literatures. Subsequent practical applications also depend on its fast response time.

[0070] As described above, it is explained that the heterojunction deep ultraviolet photodetector provided by the present invention has good performance and fast response time.

[0071] The above embodiments are only used to illustrate the technical solutions of the present invention, but the protection scope of the present invention is not limited thereto. The embodiments of the present invention and the features in the embodiments can be arbitrarily combined with each other without conflict. Any technician familiar with the technical field can easily think of changes or replacements within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method for preparing an ultra-wide bandgap semiconductor, characterized in that: The method comprises calcining a P-type gallium nitride substrate under oxygen-permeable conditions.

2. The preparation method according to claim 1, characterized in that: The calcination temperature is 900-1000° C., and the calcination time is 20 min-2 h.

3. An ultra-wide bandgap semiconductor prepared according to the preparation method of claim 1 or 2.

4. Use of the ultra-wide bandgap semiconductor according to claim 3 in the preparation of a heterojunction deep ultraviolet photodetector.

5. A method for preparing a heterojunction deep ultraviolet photodetector, characterized in that: The steps include: The ultra-wide bandgap semiconductor of claim 3 is subjected to photoresist lithography and phosphoric acid solution etching to obtain a heterojunction of gallium nitride and potassium oxide; A mask is attached to the heterojunction, and after electrode plating, a heterojunction deep ultraviolet photodetector is obtained.

6. The preparation method according to claim 5, characterized in that: The photolithography step specifically comprises coating the ultra-wide bandgap semiconductor with photoresist, baking at 95° C.-100° C. for 90s-120s, exposing for 6s, developing for 40s-60s, and then drying with a nitrogen gun.

7. The preparation method according to claim 5, characterized in that: The etching temperature is 160°C-200°C.

8. The preparation method according to claim 5, characterized in that: The electrode is a Ti / Pt / Au electrode.

9. A heterojunction deep ultraviolet photodetector obtained according to any one of the preparation methods of claims 5-8.

10. Use of the heterojunction deep ultraviolet photodetector as claimed in claim 9 in detecting deep ultraviolet light.

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