Performance study of high operating temperature HgCdTe mid wave infrared detector through numerical modeling

Abstract

The design of present generation uncooled Hg1−xCdxTe infrared photon detectors relies on complex heterostructures with a basic unit cell of type ṉ+/π/p̱+. We present an analysis of double barrier ṉ+/π/p̱+ mid wave infrared (x=0.3) HgCdTe detector for near room temperature operation using numerical computations. The present work proposes an accurate and generalized methodology in terms of the device design, material properties, and operation temperature to study the effects of position dependence of carrier concentration, electrostatic potential, and generation-recombination (g-r) rates on detector performance. Position dependent profiles of electrostatic potential, carrier concentration, and g-r rates were simulated numerically. Performance of detector was studied as function of doping concentration of absorber and contact layers, width of both layers and minority carrier lifetime. Responsivity ∼0.38 A W−1, noise current ∼6×10−14 A/Hz1/2 and D∗ ∼3.1×1010cm Hz1/2 W−1 at 0.1 V reverse bias have been calculated using optimized values of doping concentration, absorber width and carrier lifetime. The suitability of the method has been illustrated by demonstrating the feasibility of achieving the optimum device performance by carefully selecting the device design and other parameters.

Analysis of current voltage characteristics of MWIR homojunction photodiodes for uncooled operation

“…Internal radiative recombination is negligible in this case and contribution of reabsorption to net g-r process can be ignored at higher operating temperatures [15]. Our calculations in a previously published paper [13] showed that radiative g-r does not influence the model for non equilibrium mode reverse biased detectors. The relative contribution from the n + region diffusion current to the total reverse leakage current was calculated to be negligible, therefore total dark current is I total = I Auger + I SR + I TAT + I pdiff .…”

“…The dark I-V characteristics showed negative differential resistance at reverse bias in the homojunction devices. We have previously reported a one dimensional numerical device model for solution of carrier transport equations developed using finite difference method to describe the operation of these devices [13]. Using the same numerical method, we have modeled net thermal generation recombination (g-r) processes as sum of Auger, SRH and trap assisted tunneling (TAT) mechanisms on the right hand side of carrier continuity equations to simulate the experimental room temperature dark I-V characteristics.…”

Modeling of HgCdTe photodetectors in the LWIR region

“…The formulae to calculate all the basic material parameters such as bandgap, carrier mobility, intrinsic carrier concentration, effective masses and dielectric constants are well known and can be consistently found in literature [3]. All parameters used for our simulations can be found in ref 2.…”

Performance Modeling of Bandgap Engineered HgCdTe-Based nBn Infrared Detectors

“…A 1-D model has been used, which includes the electrical and optical properties of HgCdTe that are based on previously published models [6], [7]. In addition, Auger, SRH, and radiative G-R mechanisms have been included in the steady-state drift-diffusion model at all locations within the device.…”