Image transformation in integrated quantum well infrared photodetector-light emitting diode

Abstract

We present an analysis of physical effects responsible for infrared image transformation in integrated quantum well infrared photodetector-light emitting diode (QWIP-LED). For a large-area device, the spatial smearing of the transformed image is determined by the lateral photocurrent spreading in the QWIP and the lateral diffusion of carriers injected into the LED. For devices with low QWIP photocurrent gain, the spatial resolution is limited by the carrier diffusion lengths in the QWIP and in the LED active region, which are much shorter than radiation wavelength, and hence, the transformed image is practically undistorted.