Ultrafast metal-semiconductor-metal photodiodes fabricated on low-temperature GaAs

Abstract

GaAs metal-semiconductor-metal photodiodes fabricated on GaAs grown at low substrate temperatures (200 °C) have been investigated in the time domain by electro-optic sampling. It could be shown that these diodes have a faster response, a considerably reduced long time tail, and can be used at larger bias than comparable diodes produced on GaAs grown at 700 °C. Temperature-dependent measurements show that the tail can be described by hopping conductivity and disappears below 50 K.