From bulk to porous GaN crystal: precise structural control and its application in ultraviolet photodetectors†
Porous GaN has many unique merits, such as a large specific surface area, adjustable bandgap and excellent optical performance. Here, we develop a simple and effective method for preparing porous GaN single crystals through high temperature annealing. The effects of different annealing temperatures on the porous structure, crystal quality and optical properties of GaN are investigated. The relationship model of annealing temperatures, times and GaN porous structures is summarized. An ultraviolet (UV) photodetector based on porous GaN is fabricated. The effects of porous structures on the performance of the GaN UV photodetector are investigated for the first time. We found that the appropriate GaN porous structure can improve the performance of the photodetector. A possible performance enhancement mechanism has been proposed. Based on the high performance and simple fabrication process, porous GaN crystal can be an excellent candidate for UV photodetectors.