Light-induced persistence of leakage current and low frequency noise in reverse biased backside-illuminated Hg1-xCdxTe photodiodes

Backside illumination of Hg1-xCdxTe photodiodes at low temperature increases the low frequency excess noise. The photodiodes tested were formed by ion implantation of LPE Hg1-xCdxTe on CdTe substrates. During illumination, the excess noise increase is proportional to the photocurrent for backgrounds which induce a current in the 10^-5A cm^-2range. After illumination the increased dark current and excess noise in a reverse biased diode persist for hours in some of the diodes tested. Persistence is not observed after illumination for zero bias.