CN-122006782-A - GaN-based photocatalytic device based on microporous structure and preparation method thereof

Abstract

The invention discloses a GaN-based photocatalytic device based on a micropore structure, which sequentially comprises a substrate layer, an n-GaN layer, a multiple quantum well layer and a p-GaN layer from bottom to top, wherein micropores penetrating through the p-GaN layer and the multiple quantum well layer and exposing the n-GaN layer are etched on the device. Also discloses a preparation method and application thereof. The device obviously shortens the diffusion path of the liquid phase reactant to the active interface through the introduction of the micropore array structure, and promotes the rapid desorption of gas in the reaction process, thereby effectively improving the interface mass transfer efficiency of the device, further enhancing the interface reaction kinetics by the Pt catalyst loaded in the pores, and improving the hydrogen production performance of photocatalytic decomposition water. Experimental results show that under the same reaction system and illumination condition, the device has better hydrogen production performance compared with the traditional planar structure GaN-based photocatalysis device.

Inventors

• TAO TAO
• GU YIFAN
• Zheng Qiantong
• SHI WEN
• CHEN WENHAO
• LIU BIN

Assignees

• 南京大学

Dates

Publication Date

20260512

Application Date

20260414

Claims (9)

1. 1. A GaN-based photocatalytic device based on a microporous structure, which sequentially comprises the following components from bottom to top: A substrate layer; An n-GaN layer; A multiple quantum well layer; A p-GaN layer; the device is characterized in that micropores penetrating through the p-GaN layer and the multiple quantum well layer and exposing the n-GaN layer are etched on the device.
2. 2. The GaN-based photocatalytic device according to claim 1, wherein the micropores are an array of micropores, the pore diameter is 5-20 μm, the pore spacing is 5-100 μm, and the pore depth is 600-1200 nm.
3. 3. The GaN-based photocatalytic device according to claim 1, wherein the inner walls and bottoms of the micropores are loaded with Pt metal, and the loading thickness is 1-10 nm.
4. 4. The GaN-based photocatalytic device of claim 1, wherein the substrate is a sapphire substrate.
5. 5. The GaN-based photocatalytic device according to claim 1, wherein the n-GaN layer has a thickness of 1-2 μm and a doping concentration of 1X 10 18 -5×10 18 cm -3 .
6. 6. The GaN-based photocatalytic device according to claim 1, wherein the multiple quantum well layer is an InGaN/GaN multiple quantum well layer, the number of cycles is 8-20, the thickness of the InGaN well layer in each cycle is 3 nm, and the thickness of the GaN barrier layer is 15 nm.
7. 7. The GaN-based photocatalytic device according to claim 1, wherein the thickness of the p-GaN layer is 100-300 nm and the doping concentration is 1X 10 19 cm -3 -1×10 20 cm -3 .
8. 8. The method for manufacturing a GaN-based photocatalytic device according to any one of claims 1 to 7, characterized by comprising the steps of: (1) Sequentially depositing an n-GaN layer, a multiple quantum well layer and a p-GaN layer on a substrate to form a p-n junction; (2) Etching on the surface of the device to form micropores penetrating through the p-GaN layer and the multiple quantum well layer and exposing the n-GaN layer, thereby obtaining the GaN-based photocatalytic device.
9. 9. The method of manufacturing according to claim 8, further comprising the step (3) of directionally depositing metallic Pt on the inner walls of the micropores and the n-GaN region of the bottom of the micropores to obtain a GaN-based photocatalytic device.

Description

GaN-based photocatalytic device based on microporous structure and preparation method thereof Technical Field The invention relates to a GaN-based photocatalytic device based on a microporous structure and a preparation method thereof, belonging to the technical field of semiconductor photocatalysis and photoelectrochemistry. Background The photocatalytic water splitting hydrogen production is an important technical path which takes solar energy as the only energy input and can realize clean energy conversion. Compared with the traditional water electrolysis or fossil energy hydrogen production mode, the technology has the advantages of mild reaction conditions, simple system structure, environmental friendliness and the like, and therefore, the technology is widely focused. Among the many photocatalytic material systems, gaN and its related InGaN/GaN heterostructures are considered ideal material systems for constructing solid state photocatalytic devices due to their excellent chemical stability, corrosion resistance, and tunable bandgap characteristics. By constructing the p-GaN/multiple quantum well/n-GaN structure, a built-in electric field can be formed inside the device, separation and transmission of photo-generated carriers are effectively promoted, and therefore the photo-catalytic reaction efficiency is improved. However, the existing GaN-based photocatalytic devices mostly adopt a planar structure, and the reaction interface mainly depends on the diffusion process of liquid-phase reactants on a macroscopic scale, so that the mass transfer efficiency is limited. Meanwhile, the gas generated in the photocatalytic reaction process is easy to aggregate on the surface area of the plane to form bubble coverage, and the exposure of the active site and the reaction are further hindered. Even with the introduction of cocatalysts, simple material or interfacial modification is still difficult to fundamentally solve the mass transfer limitation problem caused by the planar structure. Therefore, there is a need for a GaN-based photocatalytic device that can effectively improve the mass transfer conditions of the reaction interface and further enhance the efficiency of the photocatalytic reaction through structural design without significantly increasing the complexity of the device. Disclosure of Invention The invention discloses a GaN-based photocatalytic device based on a micropore structure, which is characterized in that micropores are constructed on the surface of the device, so that the diffusion efficiency of reactants and the bubble desorption capacity are obviously improved, and the efficient photocatalytic decomposition of water to produce hydrogen is realized. The invention adopts the technical scheme that: a GaN-based photocatalytic device based on a micropore array structure sequentially comprises the following components from bottom to top: A substrate layer; An n-GaN layer; A multiple quantum well layer; A p-GaN layer; The device is etched with micropores penetrating the p-GaN layer and the multiple quantum well layer and exposing the n-GaN layer . Preferably, the micropores are micropore arrays, the pore diameter is 5-20 mu m, the pore spacing is 5-100 mu m, and the pore depth is 600-1200 nm. Preferably, the inner walls and bottoms of the micropores are loaded with metal Pt, and the loading thickness is 1-10 nm. Preferably, the substrate is a sapphire substrate. Preferably, the thickness of the n-GaN layer is 1-2 μm, and the doping concentration is 1×10 18-5×1018cm-3. Preferably, the multiple quantum well layer is an InGaN/GaN multiple quantum well layer, the period number is 8-20, the thickness of the InGaN well layer in each period is 3nm, and the thickness of the GaN barrier layer is 15 nm. Preferably, the thickness of the p-GaN layer is 100-300 nm, and the doping concentration is 1×10 19cm-3-1×1020cm-3. The invention also discloses a preparation method of the GaN-based photocatalytic device, which comprises the following steps: (1) Sequentially depositing an n-GaN layer, a multiple quantum well layer and a p-GaN layer on a substrate to form a p-n junction; (2) Etching on the surface of the device to form micropores penetrating through the p-GaN layer and the multiple quantum well layer and exposing the n-GaN layer, thereby obtaining the GaN-based photocatalytic device. Preferably, the method further comprises the step (3) of directionally depositing a metal catalyst on the inner wall of the micropores and the n-GaN region of the bottom of the micropores. The device obviously shortens the diffusion path of the liquid phase reactant to the active interface through the introduction of the micropore array structure, and promotes the rapid desorption of gas in the reaction process, thereby effectively improving the interface mass transfer efficiency of the device, further enhancing the interface reaction kinetics by the Pt catalyst loaded in the pores, and improving the hydrogen production pe