Dark Current Evaluation in HgCdTe-based nBn Infrared Detectors

A High Operating Temperature (HOT) design of MW/LWIR infrared xBn photodetector based on the HgCdTe/HgCdTe is very important. Because the operation temperature of the focal plane array (FPA) imagers is critical. In this paper, we present a theoretical study of HgCdTe-based nBn detectors at 300 Kelvin. The simulation results show that parameters such as mole fraction and the thickness of the barrier layer as well as doping of the absorber layer can be optimized for higher performance. The valence band offset in HgCdTe nBn detectors can be minimized by controlling above-mentioned parameters. Evaluation of the simulation results in a temperature of 300 Kelvin and a voltage of -0.3Volts prove that with increasing doping concentration of the absorber layer, the dark current increases about %93.23. Also, the dark current decreases approximately %95.07 by changing the mole fraction of Cd in the Hgl-xCdxTe alloy. Therefore, the simulation results indicate that the dark current has significantly decreased with increasing the “x” mole fraction of the barrier layer and decreasing the doping of the absorber layer.