Enhancing Performance of Porous Si-Doped GaN Based MSM Photodetector Using 50 Hz ACPEC

• Published in: Journal of Physics: Conference Series
• Main Author: Mahmood A.; Hassan Z.; Abd Rahim A.F.; Radzali R.; Johan Ooi M.D.; Ahmed N.M.
• Format: Conference paper
• Language: English
• Published: Institute of Physics Publishing 2020
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85086828039&doi=10.1088%2f1742-6596%2f1535%2f1%2f012006&partnerID=40&md5=0c0b4807a4f13d60e80aafec2c4a184f

In this work, we report the formation of porous Si-doped GaN films under a novel alternating current (sine-wave a.c. (50 Hz)) photo-assisted electrochemical etching (ACPEC) conditions. The formation of porous Si-doped GaN by the novel ACPEC is performed in the same electrolyte concentration (4% KOH) used in common dc constant current electrochemical etching process. Ultra-violet (UV) illumination is used to assist in the generation of electron-hole pairs, where etching proceeds through the oxidation and consequently, dissolution of the semiconductor surface. The ac formed porous Si-doped GaN with excellent structural and optical properties. According to the FESEM micrographs, the GaN thin films exhibit a homogeneous nanoporous structures with spatial nano-flakes arrangement. The porous layer exhibited a substantial photoluminescence (PL) intensity enhancement with red-shifted band-edge PL peaks associated with the relaxation of compressive stress. The shift of E2 (high) to the lower frequency in Raman spectra of the porous GaN films further confirms such a stress relaxation. Electrical characterizations of the MSM photodiodes were carried out by using current-voltage (I-V) measurements indicated that the devices were highly sensitive to ambient light. © 2020 IOP Publishing Ltd. All rights reserved.