Structure optimization of inclined AlGaN nanoarray photocathode based on three-dimensional photoemission mechanism

AlGaN nanoarray photocathodes, have broad application prospects in the fields of ultraviolet detection imaging, electron sources and solar energy. In this study, the relationship between the photoemission characteristics and the geometry parameters of inclined AlGaN nanoarrays is studied by a three-dimensional physical model with a four-step transportation process. By integrating the “four-step” model, which comprehensively considers optical absorption, electron transport, electron emission, and electron collection, with the three-dimensional carrier continuity equations of the nanorod array, the corresponding photoemission parameters are obtained and their photoemission characteristics are analyzed. The results show that for the inclined nanoarray, the maximum emitted current can be achieved at an included angle of 76°, regardless of the diameter, height, or hypotenuse length of the nanowires. When it comes to the collected current, the peak value of the collected current remains unaffected by changes in diameter. At an included angle of 76°, the collected current reaches its maximum across all diameters. However, when the height or hypotenuse length of the nanowire array varies, the peak of the collected current gradually shifts toward 70° as the height or hypotenuse length increases. This study is expected to give a theoretical insight for the emission mechanism of nanoarray photocathode and accelerate the design of nanostructure optoelectrical devices.