Low frequency noise-dark current correlations in HgCdTe infrared photodetectors

In this paper, low frequency noise and dark current correlation is investigated as a function of reverse bias and temperature for short-wave infrared (SWIR), mid-wave infrared (MWIR), and long-wave infrared (LWIR) HgCdTe homo-junction photodetectors. Modelling of dark current-voltage characteristics shows that the detectors have ohmic-behavior under small reverse bias, thus enabling further analysis of 1/f noise-current dependences with the empirical square-law relation (S-I similar to I-2) at different temperature regions. It is found that for the SWIR and MWIR devices, the total 1/f noise spectral density at arbitrary temperatures can be modelled by the sum of shunt and generation-recombination noise as S-I (T, f) = [alpha SHIISH2(T)+ alpha I-G-R(G-R)2(T)]/f, with no contribution from the diffusion component observed. On the other hand, for the LWIR device the diffusion component induced 1/f noise that cannot be overlooked in high temperature regions, and a 1/f noise-current correlation of S-I(T, f) = {alpha(s) [I-DIFF(2)(T) + I-G-R(2)(T)] alpha I-SH(SH)2(T)}/f is proposed, with a shared noise coefficient of alpha(s) congruent to 1 x 10(-9) which is close to that calculated for shunt noise. The 1/f noise-current correlation established in this work can provide a powerful tool to study the low frequency noise characteristics in HgCdTe-based photodetectors and to help optimizing the "true" detectivity of devices operating at low frequency regime. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement