High responsitivity intrinsic photoconductors based on Al/sub x/Ga/sub 1-x/N

Recently several AlGaN-InGaN devices such as blue lasers, blue-green LEDs and high frequency transistors have been reported. In past we have demonstrated GaN based intrinsic photoconductors, Schottky barrier and pn-junction detectors with a long-wavelength cutoff at 365 nm. We now report on the fabrication of true solar-blind ultraviolet photoconductive detectors with Al/sub x/Ga/sub 1-x/N active layers over basal plane sapphire substrates. For sensors with aluminum mole fractions ranging from 5 to 61%, the long wavelength cutoff can be varied from 350 to 240 nm. Photoresponsitivities as high as several hundred amperes per watt were measured for sensors with 10 /spl mu/m inter-electrode spacing.