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Low frequency noise-dark current correlations in HgCdTe infrared photodetectors.

Research paper by Liqi L Zhu, Zhuo Z Deng, Jian J Huang, Huijun H Guo, Lu L Chen, Chun C Lin, Baile B Chen

Indexed on: 06 Aug '20Published on: 06 Aug '20Published in: Optics express



Abstract

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) 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 (,)=[2()+-2()]/, 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 (,)={[2()+-2()]+2()}/ is proposed, with a shared noise coefficient of α ≅ 1 × 10 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.