Gallium oxide-aluminum oxide-based solar blind ultraviolet detector and preparation method

Abstract

The application relates to a gallium oxide-aluminum oxide-based solar blind ultraviolet detector and a preparation method thereof, which comprises a substrate, Ga2O3 nanowires grown on the substrate, an Al2O3 nanolayer deposited on the surface of the Ga2O3 nanowires, and the Al2O3 nanolayer and the Ga2O3 nanowires form Ga2O3 / Al2O3 nanowires, and all the Ga2O3 / Al2O3 nanowires constitute a composite material layer; two electrodes are arranged on the composite material layer. The application utilizes a CVD growth mechanism to directly grow Ga2O3 nanowires on the substrate, and the bulk compound semiconductor does not need to be etched, so that the compatibility of the semiconductor and the substrate is improved. The application deposits an Al2O3 nanolayer on the surface of the Ga2O3 nanowires, introduces the Al2O3 nanolayer as a cladding layer, greatly reduces the dark current, and to a certain extent, reduces the oxygen adsorption and the carried-away electrons, so that the on-off ratio is increased, and the response is improved.

Description

Technical Field

[0001] This application relates to the field of ultraviolet detector technology, and in particular to a solar-blind ultraviolet detector based on gallium oxide-aluminum oxide and its fabrication method. Background Technology

[0002] Ultraviolet (IR) photoelectric sensing systems can be used in forest fire detection, missile early warning, ultraviolet imaging, secure communications, space exploration, electrical discharge detection, and criminal investigation. Solar-blind ultraviolet detectors do not require cooling devices and are well-adapted to different environments.

[0003] In solar-blind ultraviolet imaging technology using gallium oxide (Ga2O3) focal plane arrays as the core photodetector, β-Ga2O3 material is considered one of the best candidate materials for deep ultraviolet photodetector applications due to its ultra-wide bandgap (~4.9eV), high breakdown electric field (~9MV / cm), excellent thermal stability, and high absorption coefficient for ultraviolet light.

[0004] Photodetectors using pure gallium oxide have a simple structure and fabrication process, and are inexpensive, attracting widespread attention and research. However, they still suffer from problems such as low on / off ratio and low responsivity, which seriously restrict the optimization and improvement of their photoelectric performance. Summary of the Invention

[0005] This application provides a solar-blind ultraviolet detector based on gallium oxide-aluminum oxide and its fabrication method to solve the problems of low on / off ratio and low responsivity in related technologies.

[0006] In a first aspect, a solar-blind ultraviolet detector based on gallium oxide-aluminum oxide is provided, comprising:

[0007] Substrate;

[0008] Ga2O3 nanowires grown on the substrate;

[0009] An Al2O3 nanolayer is deposited on the surface of the Ga2O3 nanowires, and the Al2O3 nanolayer and the Ga2O3 nanowires form Ga2O3 / Al2O3 nanowires, and all of the Ga2O3 / Al2O3 nanowires constitute a composite material layer.

[0010] Two electrodes are disposed on the composite material layer.

[0011] In some embodiments, the Ga2O3 nanowires have a width of 5 nm to 50 nm and a length of 100 nm to 1 mm.

[0012] In some embodiments, the thickness of the Al2O3 nanolayer is 5 nm to 20 nm.

[0013] In some embodiments, the substrate is made of aluminum oxide, silicon, or sapphire;

[0014] And / or, the thickness of the substrate is 50 μm to 300 μm;

[0015] And / or, the electrode is made of one or more of Ag, Au, C, Cu, Ti and In.

[0016] Secondly, a method for fabricating a solar-blind ultraviolet detector based on gallium oxide-aluminum oxide is provided, which includes the following steps:

[0017] Ga2O3 nanowires were grown on the substrate at a preset growth temperature;

[0018] An Al2O3 nanolayer is deposited on the surface of the Ga2O3 nanowires to form Ga2O3 / Al2O3 nanowires, and all of the Ga2O3 / Al2O3 nanowires constitute a composite material layer.

[0019] Two electrodes are disposed on the composite material layer.

[0020] In some embodiments, Ga2O3 nanowires are grown on a substrate at a preset growth temperature, including the following steps:

[0021] A catalyst film is formed on the substrate;

[0022] At a preset growth temperature, the catalyst film is shrunk into multiple catalyst particles, and Ga2O3 powder is introduced to grow Ga2O3 nanowires at the catalyst particles.

[0023] In some embodiments, the catalyst film is made of Au, Ag, or Pa;

[0024] And / or, the thickness of the catalyst film is 5 nm to 20 nm.

[0025] In some embodiments, the growth time of the Ga2O3 nanowires is 5 min to 60 min, and the preset growth temperature is 400℃ to 1000℃.

[0026] In some embodiments, the deposition temperature of the Al2O3 nanolayer is 100℃~400℃, and the growth rate is 0.05~0.2nm / cycle.

[0027] In some embodiments, the electrode is formed by applying silver paste to the composite material layer.

[0028] The beneficial effects of the technical solution provided in this application include:

[0029] This application provides a solar-blind ultraviolet detector based on gallium oxide-aluminum oxide and its fabrication method. This application utilizes the CVD growth mechanism to directly grow Ga2O3 nanowires on the substrate without etching the bulk compound semiconductor, thereby improving the compatibility between the semiconductor and the substrate.

[0030] This application deposits an Al2O3 nanolayer on the surface of Ga2O3 nanowires. Introducing the Al2O3 nanolayer as a cladding layer significantly reduces dark current and, to some extent, reduces the electrons carried away by oxygen adsorption, thereby increasing the on / off ratio and improving the responsivity. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram showing the formation of a catalyst thin film on a substrate according to an embodiment of this application;

[0033] Figure 2 This is a schematic diagram of the catalyst film condensed into catalyst particles according to an embodiment of this application;

[0034] Figure 3 for Figure 2 A schematic diagram showing the growth of Ga2O3 nanowires on the surface.

[0035] Figure 4 for Figure 3 A schematic diagram of Ga2O3 / Al2O3 nanowires formed after depositing an Al2O3 nanolayer;

[0036] Figure 5 A schematic diagram of a solar-blind ultraviolet detector based on gallium oxide-aluminum oxide provided in an embodiment of this application;

[0037] Figure 6 This is an IT curve of current versus voltage for a gallium oxide-aluminum oxide-based solar-blind ultraviolet detector provided in an embodiment of this application;

[0038] Figure 7 This is an IT curve of the current versus voltage of a solar-blind ultraviolet detector based on Ga2O3 nanowires, provided as a comparative example in this application.

[0039] Figure 8 This is an IV curve of the current change over time for a solar-blind ultraviolet detector based on gallium oxide-aluminum oxide, provided in an embodiment of this application.

[0040] Figure 9 This is a comparative example of the current-time variation (IV) curve of a solar-blind ultraviolet detector based on Ga2O3 nanowires provided in this application.

[0041] In the figure: 1. Substrate; 2. Ga2O3 nanowires; 3. Ga2O3 / Al2O3 nanowires; 4. Electrode; 5. Catalyst film; 6. Catalyst particles. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0043] See Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, this application provides a solar-blind ultraviolet detector based on gallium oxide-aluminum oxide. The solar-blind ultraviolet detector includes a substrate 1, an active region material, and electrodes 4. The active region material includes Ga2O3 nanowires 2 and an Al2O3 nanolayer. The Ga2O3 nanowires 2 are grown on the substrate 1, and there are multiple Ga2O3 nanowires 2, which are randomly or regularly distributed on the substrate 1. The Al2O3 nanolayer is deposited on the surface of the Ga2O3 nanowires 2 as an outer cladding layer, and the Al2O3 nanolayer and the Ga2O3 nanowires 2 form Ga2O3 / Al2O3 nanowires 3. All the Ga2O3 / Al2O3 nanowires 3 constitute a composite material layer, and the left and right electrodes 4 are disposed on the composite material layer.

[0044] This application utilizes a CVD growth mechanism to directly grow Ga2O3 nanowires 2 on substrate 1 without etching bulk compound semiconductors, thereby improving the compatibility between semiconductors and substrates.

[0045] In this application, an Al2O3 nanolayer is deposited on the surface of Ga2O3 nanowire 2. The introduction of the Al2O3 nanolayer as a cladding layer greatly reduces the dark current and also reduces the electrons carried away by oxygen adsorption to a certain extent, thereby increasing the on / off ratio and improving the responsivity.

[0046] See Figure 6 The figure shown is a graph of the current versus voltage (IT) curve of a solar-blind ultraviolet detector based on gallium oxide-aluminum oxide provided in an embodiment of this application.

[0047] See Figure 7 As shown, the current versus voltage (IT) curve of a solar-blind ultraviolet detector based on Ga2O3 nanowires is provided as a comparative example. The difference between this detector and the solar-blind ultraviolet detector based on gallium oxide-aluminum oxide is that it is a pure Ga2O3 nanowire 2, without depositing an Al2O3 nanolayer on the Ga2O3 nanowire 2.

[0048] from Figure 6 and Figure 7 In comparison, the detector with deposited alumina has a significantly higher on / off ratio, indicating that depositing alumina is beneficial for improving the on / off ratio of the detector.

[0049] See Figure 8 The figure shows the current versus time (IV) curve of a gallium oxide-aluminum oxide-based solar-blind ultraviolet detector provided in an embodiment of this application. As can be seen from the figure, under irradiation at a wavelength of 254 nm, the photocurrent is 100 times the dark current, and the calculated detectivity reaches 10-1. 13 Magnitude.

[0050] See Figure 9 The figure shows the current versus time (IV) curve of a solar-blind ultraviolet detector based on Ga2O3 nanowires, provided as a comparative example. The difference between this detector and a gallium oxide-aluminum oxide-based solar-blind ultraviolet detector is that this one uses pure Ga2O3 nanowires 2, without depositing an Al2O3 nanolayer on the Ga2O3 nanowires 2. As can be seen from the figure, under irradiation at a wavelength of 254 nm, the photocurrent is twice the dark current, resulting in a calculated detectivity of 10. 12 On a significant scale, the on / off ratio of the deposited Al2O3 nanolayer was clearly increased by 50 times compared to the undeposited Al2O3 nanolayer.

[0051] Depositing an Al2O3 nanolayer on Ga2O3 nanowires can significantly improve performance, mainly because the Al2O3 nanolayer can reduce oxygen adsorption, thereby reducing the probability of adsorbed oxygen combining with electrons.

[0052] For the size of Ga2O3 nanowires 2, the thinner the better, because the nanoscale and quantum scale have special optical, electrical, and thermal effects, and the longer the better, in extreme cases, it is possible to fabricate devices by hand and mass-produce them. Therefore, the width of Ga2O3 nanowires 2 is 5nm to 50nm, and the length is 100nm to 1mm.

[0053] If the Al2O3 nanolayer is too thin, it will not achieve the above-mentioned function, while if it is too thick, it will affect light absorption. Therefore, in some preferred embodiments, the thickness of the Al2O3 nanolayer is 5nm to 20nm.

[0054] There are several options for the material of the substrate 1. For example, as an example, substrate 1 is made of aluminum oxide. As another example, substrate 1 is made of silicon. Sapphire can also be selected.

[0055] To ensure insulation and reduce leakage current, in some preferred embodiments, the thickness of substrate 1 is 50 μm to 300 μm.

[0056] The material of the electrode 4 can be selected from a variety of options, such as one or more of Ag, Au, C, Cu, Ti and In.

[0057] See Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown in the embodiments of this application, a method for fabricating a solar-blind ultraviolet detector based on gallium oxide-aluminum oxide is also provided, which includes the following steps:

[0058] 101: Ga2O3 nanowires 2 are grown on substrate 1 at a preset growth temperature.

[0059] In order to successfully grow Ga2O3 nanowires 2, the growth time of Ga2O3 nanowires 2 is 5 min to 60 min, and the preset growth temperature is 400℃ to 1000℃.

[0060] In step 101 above, Ga2O3 nanowires 2 are grown on substrate 1 at a preset growth temperature, including the following steps:

[0061] 201: Magnetron sputtering is performed on substrate 1 to form a catalyst film 5;

[0062] There are many choices for the material of the catalyst film 5. For example, Au can be used, or Ag or Pa can be used, etc. The thickness of the catalyst film 5 is 5nm to 20nm.

[0063] 202: At a preset growth temperature, the catalyst film 5 is shrunk into multiple catalyst particles 6, and Ga2O3 powder is introduced. Using a CVD growth mechanism, Ga2O3 nanowires 2 are grown at the catalyst particles 6.

[0064] 102: On the surface of Ga2O3 nanowires 2, an Al2O3 nanolayer is deposited using atomic deposition (ALD) technology to form Ga2O3 / Al2O3 nanowires 3, and all Ga2O3 / Al2O3 nanowires 3 constitute a composite material layer.

[0065] In order to successfully deposit the Al2O3 nanolayer, the deposition temperature of the Al2O3 nanolayer is 100℃~400℃, and the growth rate is 0.05~0.2nm / cycle.

[0066] 103: Two electrodes, left and right, are formed on the composite material layer.

[0067] The material of the aforementioned electrode 4 can be selected from various options, such as one or more of Ag, Au, C, Cu, Ti, and In. As an example, if Ag is used, the left and right electrodes 4 can be formed on the composite material layer by silver paste dotting.

[0068] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0069] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0070] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for fabricating a solar-blind ultraviolet detector based on gallium oxide-aluminum oxide, characterized in that, Solar-blind ultraviolet detectors include: Substrate (1); Ga2O3 nanowires (2) grown on the substrate (1); the width of the Ga2O3 nanowires (2) is 5nm~50nm and the length is 100nm~1mm; An Al2O3 nanolayer is deposited on the surface of the Ga2O3 nanowire (2), and the Al2O3 nanolayer and the Ga2O3 nanowire (2) form Ga2O3 / Al2O3 nanowire (3), and all the Ga2O3 / Al2O3 nanowires (3) constitute a composite material layer; the thickness of the Al2O3 nanolayer is 5nm~20nm; Two electrodes (4) are disposed on the composite material layer; The preparation method includes the following steps: A catalyst film (5) is formed on a substrate (1); at a growth temperature of 400℃~1000℃, the catalyst film (5) is condensed into multiple catalyst particles (6), and Ga2O3 powder is introduced to grow Ga2O3 nanowires (2) at the catalyst particles (6). An Al2O3 nanolayer is deposited on the surface of the Ga2O3 nanowire (2) to form Ga2O3 / Al2O3 nanowire (3), and all of the Ga2O3 / Al2O3 nanowire (3) constitute a composite material layer; Two electrodes (4) are disposed on the composite material layer.

2. The method for fabricating a solar-blind ultraviolet detector based on gallium oxide-aluminum oxide as described in claim 1, characterized in that: The substrate (1) is made of aluminum oxide, silicon or sapphire; And / or, the thickness of the substrate (1) is 50 μm to 300 μm; And / or, the electrode (4) is made of one or more of Ag, Au, C, Cu, Ti and In.

3. The method for fabricating a solar-blind ultraviolet detector based on gallium oxide-aluminum oxide as described in claim 1, characterized in that: The catalyst film (5) is made of Au or Ag; And / or, the thickness of the catalyst film (5) is 5 nm to 20 nm.

4. The method for fabricating a solar-blind ultraviolet detector based on gallium oxide-aluminum oxide as described in claim 1, characterized in that: The growth time of the Ga2O3 nanowires (2) is 5 min to 60 min.

5. The method for fabricating a solar-blind ultraviolet detector based on gallium oxide-aluminum oxide as described in claim 1, characterized in that: The deposition temperature of the Al2O3 nanolayer is 100℃~400℃, and the growth rate is 0.05~0.2nm / cycle.

6. The method for fabricating a solar-blind ultraviolet detector based on gallium oxide-aluminum oxide as described in claim 1, characterized in that: The electrode (4) is formed by applying silver paste to the composite material layer.

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