Optimal Dark Current Reduction in Quantum Well 9 μm GaAs/AlGaAs Infrared Photodetectors With Improved Detectivity

In this paper, an optimization approach is presented to decrease the dark current in GaAs/AlGaAs QWIPs. Dark current noise, as shown, can be reduced by increasing Al density in barriers, decreasing detector dimensions and increasing the periodic length of the structure. It is also shown that 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 (11 nA) and detectivity of 10¹² cm(Hz)^1/2/W which is an order of magnitude greater than the present values.