量子阱红外探测器光敏元参数测试

摘要

Because the photosensitive cell of Quantum Well Infrared Photodetector(QWIP) has the disadvantage of low sensitivity and strict testing condition,an applicable working environment is set up based on the full study of the working principle of QWIP. The output current and resistance of 8?9 m GaAs/AlGaAs QWIP in different temperature and different bias are measured under liquid nitrogen cooling. The output current is extremely weak,it must be magnified and filtered by a current preamplifier and locked - in amplifier in turn. The relationship between resistance and temperature, current and temperature,dark current and temperature is obtained. This relationship not only verifies the negative temperature coefficient of resistance of the detector, but also quickly determines the efficiency of photosensitive cell. LABVIEW8. 0 accomplishes data processing, analysis and display. According to the analysis of experimental results, the dark current decreases with temperature decreasing, and the photocurrent increases as the temperature declines. It indicates that the performance of QWIP has been found to enhance step by step along with decreasing of the operating temperature.%针对量子阱红外探测器(QWIP)光敏元灵敏度低,参数测试条件苛刻的局限,在充分研究其工作原理的前提下,构建了其工作环境,设计了多个参数的测试方案.在液氮制冷条件下测试了8～9 m GaAs/AlGaAs量子阱红外探测器的电阻温度特性、电流温度特性,利用电流前放和锁相放大依次对QWIP的输出电流信号进行选频放大,测试其光电流,得到了QWIP光敏元电阻与温度的对应关系,验证了器件的负电阻温度特性,进而可以快速判断探测器光敏元的有效性.测试采用LabVIEW8.0进行数据处理、分析及显示.通过对实验数据的分析,QWIP的阻抗随温度的降低呈指数上升,暗电流随着工作温度的降低而减小,光电流随着温度的降低而增大,表明探测器的性能随工作温度的降低而逐步增强.