Comparison study on light trapping of GaN UV photocathode

摘要: Abstract To obtain optimal light absorption of GaN photocathode, the spectra photocathode have been studied under different emission layer thicknesses, buffer thicknesses and materials in detail based on finite difference time domain (FDTD) method. The results show that, whether is reflection-mode or transmission-mode, its has same characteristics trends. appropriate thickness range 100–150 nm, at this time, maximum efficiency can be achieved. For with ultra-thin layer, AlN becomes an important factor affecting trapping. Compared Al composition cause a more significant change spectrum. In addition, spectrum x Ga 1−x N variable as also studied. It found that although compositions generate built-in electric field to help electrons escape, it would reduce trapping incident light, narrow sideband, shift cutoff wavelength below 300 nm, which suitable for “sun blind” detection applications. Our research provide theoretical guidance designing photocathodes properties.