D X centers in AlGaAs p-n heterojunctions and heterojunction bipolar transistors

Abstract
DX centers are found to cause the capacitance of an AlGaAs/GaAs pn heterojunction at 77 K to behave like that of a pin diode. Exposure to light causes the capacitance to behave like a normal pn junction. It is argued that the presence of DX centers has only a small effect on the switching properties heterojunction bipolar transistors.