High Responsivity, Bandpass Near-UV Photodetector Fabricated From PVA- $\hbox{In}_{2}\hbox{O}_{3}$ Nanoparticles on a GaN Substrate

High photoresponsivity in the near-ultraviolet (UV) range was observed for a photodetector fabricated from polyvinyl-alcohol (PVA)-coated In
₂
O
₃
nanoparticles. The high responsivity is due to large depletion region introduced by ion-adsorbed oxygen on the surface of In
₂
O
₃
nanoparticles. Experiments demonstrated that the photodetector exhibited either a low-pass or bandpass spectral response, depending on the illumination directions. Transient characteristics of photoconductivity have been studied, which shows a rise time of 700 s and a fall time of 1350 s.