Back illuminated solar-blind photodetectors

The desire for shorter-wavelength devices has drawn attention to Al/sub x/Ga/sub 1-x/N devices, which are sensitive in the ultraviolet (UV) regime. In particular, for military applications requiring detection of objects moving in front of the sun, a photodetector must have a photoresponse only in the solar-blind region (280 nm) where the atmosphere absorbs most of the ultraviolet radiation emitted by the sun. In this paper we report on back-illuminated solar-blind devices using Al/sub 0.6/Ga/sub 0.4/N as window layers and Al/sub 0.4/Ga/sub 0.6/N as absorption layers.