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

K. Al-Heuseen a and M.R. Hashima aAl-Balqa, Applied University, Ajloun University College, Jordan bSchool of Physics, Universiti Sains Malaysia, 11800 Penang, Malaysia

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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-off 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.

DOI: 10.12693/APhysPolA.121.71 PACS numbers: 78.67.Rb, 42.79.Pw