Lateral photocurrent spreading in single quantum well infrared photodetectors

Lateral physical effects in single quantum well infrared photoeletectors (SQWIPs) under nonuniform illumination over the detector area are considered. These effects are due mainly to the in-plane transport of the photoinduced charge in the QW. The length of the lateral photocurrent spreading is determined by the in-plane conductivity of the carriers in the QW and characteristic time of the QW recharging, and can be as large as 10(1)-10(4) mu m. Closed-form analytical expressions for SQWIP responsivity for modulated infrared signal and modulation transfer function are obtained. Possible techniques to suppress lateral photocurrent spreading are discussed. (C) 1998 American Institute of Physics.