背景辐射对甚长波碲镉汞光导器件性能的影响

Influence of background radiation on extremely-long-wave HgCdTe photoconductive detector

通过对甚长波碲镉汞器件的信号、噪声、有效寿命等的测试分析,研究背景辐射对甚长波器件性能的影响。利用冷光阑和黑体照射改变器件接收的背景辐射,设计并搭建了变背景有效寿命测试装置。改变背景辐射,测试甚长波器件的电阻、信号、噪声、噪声频谱、有效寿命。测量结果表明,增加立体角为30°的冷光阑后,随着背景辐射的减小,器件的电阻、信号、噪声、探测率等都有不同程度的增加;噪声频谱测试证明,1kHz频率处的噪声主要是产生-复合噪声;改变黑体温度的变背景的有效寿命测试结果证明,背景辐射对寿命的影响很大,背景辐射减小,光生载流子的有效寿命增加。分析甚长波器件表面和体内的S-R复合、俄歇复合、辐射复合等复合机制,利用非平衡载流子和器件有效寿命理论对器件的寿命和产生复合噪声随背景辐射的变化进行理论计算,计算结果与实验结果存在一定的差异,但在随背景辐射变化的趋势上一致,并对两者的差别进行了分析。

Based on the measurement and analysis of signal, noise and the effective lifetime, the influence of background radiation on extremely-long-wave HgCdTe infrared detectors was studied. The diaphragm and blackbody was used to change the background radiation that reached to the detectors. In order to measure the effective lifetime, an experimental setting of lifetime changing with radiation was designed and established. After setting a diaphragm of 30°, the resistor, signal, noise and detectivity of HgCdTe detectors were all increased.The noise spectrum showed that the g-r noise was dominating at 1 kHz frequency. The result of lifetime experiment proved that the background infected the effective lifetime deeply. As the radiation decreased, the carrier lifetime increases. Based on the analysis of S-R recombination, Auger recombination and radiation recombination in surface and bulk of the HgCdTe detectors, the calculation of effective lifetime and g-r noise are performed by using carriers and effective lifetime theory. Although the difference between the experiment and the theory exists, they have the similar trends as performance changing. At last the difference between them was also analyzed.