1/f noise in Hg1-xCdxTe detectors

Arvind I. D'Souza; Maryn G. Stapelbroek; Stacy A. Masterjohn; Priyalal S. Wijewarnasuriya; Roger E. DeWames; G. M. Williams

doi:10.1117/12.478850

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5 August 2002 1/f noise in Hg_1-xCd_xTe detectors

Arvind I. D'Souza, Maryn G. Stapelbroek, Stacy A. Masterjohn, Priyalal S. Wijewarnasuriya, Roger E. DeWames, G. M. Williams

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Proceedings Volume 4721, Infrared Detectors and Focal Plane Arrays VII; (2002) https://doi.org/10.1117/12.478850
Event: AeroSense 2002, 2002, Orlando, FL, United States

Abstract

This paper investigates 1/f noise performance of Hg_1-xCd_xTe photovoltaic detectors when detector current is varied by changing detector area, bias, temperature and incident flux. Holding detector bias and temperature constant, measured 1/f noise current is proportional to the detector current. However for all detector areas measured, non-uniformity is observed in the noise current due to the varied quality of the detectors. Even for the λ_c=16μm , 4-μm-radius, diffusion-limited detectors at 78K held at reverse bias, the average and standard deviation in dark current is I_d=9.76+/- 1.59x10^-8A while the average and standard deviation in noise current at 1 Hz in a 1 Hz bandwidth is i_n=1.01+/- 0.63x10^-12A. For all detector areas measured at 100 mV reverse bias, the average and standard deviation in dark current to noise current ratio is α _D=i_n/I_d=1.39+/- 1.09x10^-5. Defects are presumed resident in the detectors that produce greater non- uniformity in the 1/f noise as compared to the dark current at 100 mV reverse bias. Noise was also measured as a function of temperature for two λ _c=16 micrometers detectors from 55 K to 100 K. The average and standard deviation in the noise current to dark current ratio is α_D=i_n/I_d=2.36+/- 0.83x10^-5 for the 26-micrometers -diameter detector and (alpha) _D=1.71+/- 0.69x10^-5 for the 16-micrometers -diameter detector. Dark and noise current were measured while changing the bias applied to a detector. In the diffusion-limited portion of the detector I-V curve, 1/f noise is independent of bias with α _D=i_n/I_d=1.51+/- 0.12x10^-5. When tunneling currents dominated, α_T=i_n/I_d=5.21+/- 0.83x10^-5. The 1/f noise associated with tunneling currents is a factor of three greater than the 1/f noise associated with diffusion currents. In addition, 1/f noise was measured on detectors held at -100 mV and 78 K under dark and illuminated conditions. The average noise to current ratio α_D was approximately 1.5 x 10^-5 for dark and photon-induced diffusion current. However, detector-to-detector variations exist even within a single chip. The two most important points are that non-uniformities in material/fabrication need to be addressed and that each individual type of current component has an associated 1/f noise current component, the magnitude of the relationship being different depending on the source current.

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Arvind I. D'Souza, Maryn G. Stapelbroek, Stacy A. Masterjohn, Priyalal S. Wijewarnasuriya, Roger E. DeWames, and G. M. Williams "1/f noise in Hg_1-xCd_xTe detectors", Proc. SPIE 4721, Infrared Detectors and Focal Plane Arrays VII, (5 August 2002); https://doi.org/10.1117/12.478850

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