Improved external quantum efficiency of GaN p-i-n photodiodes with a TiO2 roughened surface

Abstract

Gallium nitride p-i-n ultraviolet photodiodes (PDs) with a titanium dioxide (TiO2) nano-particles roughened surface have been fabricated. It was found that the responsivity and external quantum efficiency can be improved 60% on the surface roughened PDs. It was also found that light absorption can be enhanced from various incident angles by the TiO2 roughened surface. Furthermore, the high detectivity of 9.2 x 10(1.3) cm.Hz(1/2).W-1 can be achieved from the PD with a rough surface.