Enhancing Responsivity of Porous GaN Metal-Semiconductor-Metal Ultraviolet Photodiodes by Using Photoelectrochemical Etching

Abstract

In this paper porous and as-grown GaN metal‐semiconductor‐metal photodiodes with Ni contact electrodes were fabricated. Structural and optical properties were studied of the both samples. Both detectors show a sharp cut-o wavelength at 370 nm, with a maximum responsivity of 0.14 A/W and 0.065 A/W achieved at 360 nm for porous GaN and as-grown metal‐semiconductor‐metal photodetectors, respectively. The metal‐semiconductor‐ metal photodiode based on porous GaN shows enhanced twice magnitude of responsivity relative to the as-grown GaN metal‐semiconductor‐metal photodiode. Enhancement of responsivity can be attributed to the relaxation of stress and reduction of surface pit density in the porous sample. The porous sample showed a significantly low dark current at 5 V as compared to as grown sample. PACS: