Plasmon-Enhanced Hot-Electron Photodetector Based on Au/GaN-Nanopillar Arrays for Short-Wave-Infrared Detection

Abstract

The complex device structure and costly preparation process have hindered the development and application of the GaN-based ultraviolet and infrared (UV–IR) dual-color photodetector. In this work, we designed and prepared an Au/GaN-nanopillar-based hot-electron photodetector that can operate in the short-wave infrared range, well below the GaN bandgap energy. A suitable Schottky barrier height was developed for a higher photo-to-dark current ratio by post-etching annealing. The surface plasmons generated by Au/GaN-nanopillar arrays could effectively improve the light absorption efficiency. As a result, compared with the planar device, the responsivity of the Au/GaN-nanopillar device could be enhanced by about two orders of magnitude. With the advantages of a simple structure and easy preparation, the proposed devices are promising candidates for application in UV–IR dual-color photodetection.