Measurement of minority carrier lifetime in infrared photovoltaic detectors using parallel circuit method

Abstract

An experimental method for extracting the minority carrier lifetime of a pnjuntion-type HgCdTe infrared photodetector by transient photovoltage technique is reported. The photovoltaic response of the detector is induced by a picosecond pulsed infrared laser irradiation. A small resistance is paralleled with the photodiode to minimize the influence of the junction RC constant on the photovoltaic response curve. By fitting the exponential decay phase, the time constant has been obtained which is regarded as the minority carrier lifetime of the photodiode. The carrier lifetime extracted from the experiment is in the range of 0.7-110 ns at 77 K. It is found that the minority carrier lifetime shows an increasing trend with in the increased Cd composition and pixel dimension.

Experimental Determination of Effective Minority Carrier Lifetime in HgCdTe Photovoltaic Detectors Using Optical and Electrical Methods

“…In order to minimize the effects of the equivalent junction, we can parallel a small resistance in the load circuit of the photodiode in the transient photovoltage measurement, which is called the small parallel resistance (SPR) method [10]. In this situation, the load resistance combines with the junction series resistance to parallel with the junction shunt resistance.…”

“…Since the investigation of the carrier lifetime is beneficial to understand the recombination mechanism, the measurements must be carried out on the actual devices to extract the minority carrier lifetime. Here, on the junction type HgCdTe IRFPA, we compare minority carrier lifetimes measured by PIOCVD method [8,9], SPR method [10], and PRT [11] for a series of Cd compositions and the pixels dimensional area.…”