Photocurrent enhancement of Al x Ga1-x N nanowire arrays photodetector based on coupling effects of pn junction and gradient component

Ultraviolet photodetector has a variety of applications in medical diagnosis, civilian testing and military security. The enhancement of photo response has far been a hot topic regrading to the performance improvement of the devices. In this study, we proposed a self-powered photodetector based on Al (x) Ga1-x N nanowire arrays (NWAs) utilizing axial pn junction integrating with gradient Al component. The merit of the coupling structure is demonstrated by theoretical model and simulations. The photoelectric conversion model is built based on a continuity equation derived by its corresponding boundary conditions. The photocurrent for a single nanowire and NWAs are respectively obtained. According to the simulation results of a single nanowire, the optimal nanowire height is obtained with a photocurrent enhancement up to 330%. For NWAs, the aspect ratio of NWAs and incident angle of light synergistically determine the output photocurrent. The optimal aspect ratio for NWAs is 1:1 with an optimal incident angle of 57 degrees. This study provides a reliable method for the design of photodetectors with micro-nano structures.

Automated summary

The study proposed a self-powered photodetector based on Al (x) Ga1-x N nanowire arrays, and demonstrated the advantages of the coupling structure through theoretical models and simulations. This research provides a reliable method for designing photodetectors with micro-nano structures.