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Proceedings Paper

Rectification in metal-semiconductor-metal detectors used as optoelectronic mixers
Author(s): Paul H. Shen; Keith Aliberti; Michael R. Stead; William C. Ruff; Barry L. Stann
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Paper Abstract

Variation in rectification current with ac-bias frequency has recently been observed in metal-semiconductor-metal (MSM) detectors when utilized as optoelectronic mixers in a frequency-modulated continuous-wave (FM/cw) LADAR System. This current degrades the performance of the LADAR System by inducing false targets. In this paper, we present a detailed experimental and theoretical investigation on the origin of this current. We find that MSM detectors exhibit asymmetric current-voltage characteristics that are related to imperfections in device design and processing. We also find that, although the asymmetry is usually small, a rectification current may exist even under zero mean ac bias. Both the dark current and the photocurrent exhibit asymmetric behavior, but have opposite asymmetry with respect to one another. Under transient bias voltage the device shows two transient current responses: (1) a fast one related to the displacement current and (2) a slow one related to the removal of carriers from the device. The asymmetry in current related to the slow process is opposite to the dc asymmetry, while the asymmetry in current related to the fast process is more symmetric. The rectification current varies not only with ac voltage and optical power, but also with ac bias frequency.

Paper Details

Date Published: 5 August 2002
PDF: 11 pages
Proc. SPIE 4721, Infrared Detectors and Focal Plane Arrays VII, (5 August 2002); doi: 10.1117/12.478855
Show Author Affiliations
Paul H. Shen, Army Research Lab. (United States)
Keith Aliberti, Army Research Lab. (United States)
Michael R. Stead, Army Research Lab. (United States)
William C. Ruff, Army Research Lab. (United States)
Barry L. Stann, Army Research Lab. (United States)

Published in SPIE Proceedings Vol. 4721:
Infrared Detectors and Focal Plane Arrays VII
Eustace L. Dereniak; Robert E. Sampson, Editor(s)

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