Plasmon-enhanced absorption in dielectric layer coated III-V nanowire array decorated with nanoparticles

Abstract

The group III-V nanowires (NWs) have broad prospects in the field of photoelectric detection, among which GaN and InN NWs are promising candidates for ultraviolet (UV) and short-wave infrared (SWIR) photodetectors but have rarely been studied in depth. Furthermore, there is a lack of research on the further improvement of their photoelectric performance. In this research, we introduce a thin dielectric layer in the structure of nanowire array decorated with metal nanoparticles (NPs) for the first time, demonstrating how dielectric layer between NWs and NPs further improve light absorption efficiency. Surface plasmons (SPs) excited by NPs, along with the dielectric layer which can concentrate the incident light, result in obvious enhancement of the absorption rate, the rationality of this design is supported by the calculation results in both ultraviolet UV and SWIR range. For GaN NWs, light absorption rate can be increased from 76 % to 96 % near 335 nm and for InN NWs the peak of absorption curve rises from 49 % to 97 % near 1550 nm. The simulation results will provide a reference for improving the performance of photodetectors.