Optimal dark current reduction in quantum well 9 μm GaAs/AlGaAs infrared photodetectors with improved detectivity

Abstract

In this research, an optimization approach is presented to decrease the dark current in GaAs/AlGaAs QWIPs. The dark current noise is reduced by increasing Al density in barriers, decreasing detector dimensions and increasing the periodic length of the structure. In addition, increasing the number of periods can reduce both the dark current and responsivity. Therefore, devices can be optimally designed through judicious choice of these parameters. An optimal photodetector structure is designed and simulated to achieve low dark current (11nA) and detectivity of 1.4×1012cm(Hz)1/2/W which is an order of magnitude greater than the present values. © 2008 Science Publications.