A novel high sensitivity p-i-n MODFET photodetector using low-temperature-MBE grown GaAs

A novel, high sensitivity photodetector which combines a p-i-n diode and a modulation doped field effect transistor (MODFET) in a single device is reported for the first time. There are two possible modes of operation of the device, a vertical p-i-n mode and a lateral MODFET mode. The device exhibits a high responsivity of /spl sim/95 A/W in the MODFET mode which is /spl sim/6000 times that in the p-i-n mode. The device also has significant photo-response in the GaAs subbandgap region arising from the arsenic clusters and/or the traps present in the low-temperature grown GaAs layer.