光伏型碲镉汞探测器在波段内连续激光辐照下的两种不同过饱和现象的产生机理

Generation mechanism of two different over-saturation phenomena of photovoltaic HgCdTe detectors irradiated by CW band-in laser

利用连续波段内激光对两批光伏型碲镉汞探测器进行了激光辐照实验,发现了两种不同的过饱和现象.实验表明,光伏型碲镉汞探测器在强光辐照下都会出现开路电压随光强增强而减小的过饱和现象,明晰了PV型探测器在强光辐照下的一般规律性现象和由探测器个体差异导致的特殊现象.从等效电路模型出发,剖析了两种过饱和现象的发生条件,建立了数值计算的理论模型,对两种过饱和现象进行了数值模拟,计算结果与实验结果符合得较好.研究表明,光伏型碲镉汞探测器在波段内强光辐照下引起的过饱和现象有两种产生机理,一种是热效应引起的暗电流增大机理;另一种是探测器材料中缺陷引起的漏电流增大机理.

We have studied two batches of photovoltaic HgCdTe detectors irradiated by CW band-in laser, and discovered, two different over-saturation phenomena. It is shown that the over-saturation phenomenon associated with the open-circle voltage signals which decreases with increasing light intensity is of universal existence in the PV HgCdTe detectors irradiated by intense light. The regular and special phenomena of PV HgCdTe detectors under intense light radiation are definite and obvious. The generation conditions for the two typical over-saturation phenomena are analyzed in terms of the equivalent circuit model. These two kinds of over-saturation phenomena have been numerically simulated. Numerical results are in good agreement with experimental data. It is found that the two generation mechanisms of the over-saturation phenomena of PV detector under irradiation of the above-band gap laser do exist. One is the increasing dark current due to thermal effectm, and the other is the leak current due to the bugs in the detector material.