甚长波指的是波长大于14μm的波段,该波段富含大量的信息,包括大气中的湿度和CO2的含量,以及云层的结构和温度的轮廓,这些对大气遥感探测是必须的。采用在CdZnTe衬底上液相外延生长的As掺杂P型材料上进行B+离子注入形成平面结,制成了在液氮温度下,截止波长达到14μm的单元变面积结构和小的焦平面器件。测试结果显示,甚长波器件有反向的开启现象,可能是甚长波器件表面发生反型造成的。单元变面积器件的测试结果显示,甚长波表面电流与体电流是可以比拟的,即表面漏电较大。而变温测试发现,甚长波器件在温度低于50K时,隧穿电流占主导。在60μm×60μm中心距的小面阵器件中,50Iμm×50μm的光敏元I-V特性最差。
This paper describes the study of very long wavelength infrared (VLWIR, λc〉14 μm) HgCdTe detectors, used for the remote atmosphere sounding. The very long wavelength band is particularly rich in information about humidity and CO2 levels and provides additional information about cloud structure and temperature distribution across the atmosphere. According to the results, it is shown that the VLWIR HgCdTe detectors have abnormal current-voltage phenomenon at a low temperature, which may be the results of a parasite pn junction. Besides, through data analysis and curves fitting, it is shown that the surface current of the VLWIR HgCdTe diodes is nearly comparable with the bulk current, which reflects that the surface effect is large in the VLWIR HgCdTe diodes. Through the results, it proves that the passivation of diodes is very important.