Solar-Blind p-GaN/i-AlGaN/n-AlGaN Ultraviolet Photodiodes on SiC Substrate

Abstract

Ultraviolet p-i-n photodiode structures have been fabricated using AlGaN/GaN and GaN structures grown on 6H-SiC. GaN photodiodes grown on 6H-SiC had lower leakage than GaN grown on sapphire. Solar-blind p-GaN/i-Al x Ga 1-x N./n-Al x Ga 1-x N (x 0.35) diodes were investigated. Leakage currents were measured to be as low as 10 nA/cm 2 at -5 V. Use of a thick insulating buffer resulted in a peak responsivity of 0.08 A/W at a wavelength of 292 nm, corresponding to an external quantum efficiency of 35%.