Self-Powered Ga₂O₃ MSM Solar-Blind UV PDs With Asymmetric Electrodes for Optical Communications

Abstract

This work demonstrated a self-powered Ga2O3-based metal–semiconductor–metal solar-blind ultraviolet photodetector using the following asymmetric electrodes at varying size ratios: a Schottky interdigitated electrode with wide fingers and an ohmic interdigitated electrode with narrow fingers. At a bias of 0 V, the responsivity of the device featuring Schottky electrode to ohmic electrode size ratios of 8:1 is 3.64 mA/W. Thus, increasing electrode size ratios led to significant enhancements in device self-powered performance. Leveraging the energy band structure theory, we elucidated the rationale behind the improved self-powered performance of the devices, attributing it to the broadening of the depletion region at the metal–semiconductor interface, which facilitated photogenerated carrier transport. The device exhibited a high responsivity of 495 A/W under a forward bias of 10 V while still maintaining a considerable responsivity of 16.7 A/W under a reverse bias of 10 V. Additionally, the device realizes UV optical communication adopting international Morse code.