Study of effect of surface fixed positive charges on HgCdTe photoconductive detectors

For HgCdTe photoconductive and photovoltaic detectors, the surface passivation is required. The surface physics and chemistry characteristics could be dominated by the technology of passivation. This paper reports the effect of HgCdTe anodic oxide interface on the performance of HgCdTe photoconductive detectors. Using the formulas obtained in the present paper, considering the effect of surface recombination velocity, the responsibility, noise and detectivity of Hg_0.8Cd_0.3Te photoconductive detectors operating at 77 K are calculated with 300 K background and 2 (pi) field of view. In order to understand the effect of anodic oxide interface and improve the performance of HgCdTe infrared detectors, the relation among surface fixed positive charges, surface recombination velocity and the thickness of detector is discussed.