Numerical Simulation of Third-Generation HgCdTe Detector Pixel Arrays

In this paper, we present a physics-based full 3-D numerical simulation model of third-generation infrared (IR) detector pixel arrays. The approach avoids geometrical simplifications typical of 1-D and 2-D models that can introduce errors which are difficult to quantify. We have used a finite-difference time-domain technique to compute the optical characteristics including the reflectance and the carrier generation rate in the device. Subsequently, we employ the finite-element method to solve the drift-diffusion equations on a mixed-element grid to compute the electrical characteristics including the I(V) characteristics and quantum efficiency. Furthermore, we have used this model to study HgCdTe two-color detectors that operate in the medium-wave to long-wave IR and photovoltaic pixel arrays employing a photon-trapping structure realized with a periodic array of pillars that operate in the medium-wave IR.