光伏碲镉汞探测器在波段内连续激光辐照下的非线性响应机理研究

利用波段内连续激光, 辐照禁带宽度为0.33 eV的中波光伏碲镉汞探测器. 实验结果表明, 随着辐照激光光强的逐渐增大, 探测器从线性响应过渡为非线性响应. 当探测器进入非线性状态, 探测器的开路电压随激光光强的增大而减小, 且在激光开启辐照时开路电压信号迅速下跳, 在激光停止辐照时开路电压信号迅速上跳. 通过考虑激光辐照下探测器的温度场分布以及温度对p-n结内建电场的影响, 结合考虑机械快门在开启和关闭时对激光光强变化的影响, 建立了光伏探测器在波段内连续激光辐照下的解析模型, 模型计算结果与实验结果吻合得较好. 研究表明, 激光辐照过程中的非线性响应, 主要由温度对p-n结内建电场的影响决定, 激光开启和关闭时的开路电压的幅值是由光强和温度共同决定.

Investigation of the nonlinear response mechanism of photovoltaic HgCdTe detector irradiated by CW band-in laser

The medium wave HgCdTe photovoltaic detector（band gap～0.33 eV） is irradiated by a CW band-in laser.The experimental results are shown that the detector enter into nonlinear response state as the incidence laser power increase.When the detector entered into nonlinear response state,the open circle voltage(V_oc) signal decreased with the laser power.The V_oc signal rapidly decreased when the laser turned on and the V_oc signal rapidly increased when the laser turned off.The effect of laser induced temperature field and temperature dependence built-in field of pn junction were considered.The laser power variation of laser turn on and turn off were aslo considered.The analytical model of photovoltaic detector irradiated by above-band gap CW laser was built up.The calculation results agree well with the experiment results.It is shown that the temperature dependence built-in field of pn junction is the main mechanism induced the nonlinear response.The magnitude of V_oc signals with laser turn on and turn off is decided by light intensity and temperature.