Abstract
GaAs/Al/sub 0.3/Ga/sub 0.7/As short wavelength metal-semiconductor-metal photodetectors (MSM-PDs), compatible with GaAs heterostructure MESFET technologies have been fabricated. Detector bandwidths greater than 3.5 GHz were observed for lambda =800-850 nm. Due to the GaAs/AlGaAs heterojunction, low-frequency gain which is observed in GaAs MSM-PDs was minimized. The internal quantum efficiency was close to 100% and the dark currents were less than 1 nA for large-area detectors.