吸收层特性和异质结界面电荷对12.5μm长波HgCdTe光伏探测器响应率的影响研究  

Effects of absorption layer parameters and hetero-interface charge on photoresponse of 12.5 μm long-wavelength HgCdTe photodiode

作　　者：胡伟达[1] 殷菲[1] 叶振华[1] 全知觉[1] 胡晓宁[1] 李志锋[1] 陈效双[1] 陆卫[1] 

机构地区：[1]中国科学院上海技术物理研究所,红外物理国家重点实验室,上海200083

出　　处：《物理学报》2009年第11期7891-7896,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:60576068;60706012;10734090;10747162);上海-应用材料研究与发展基金(批准号:08520740600);航空科学基金(批准号:20080190001)资助的课题~~

摘　　要：研究了12.5μm长波HgCdTe探测器的吸收层厚度和异质结界面电荷对器件光响应率的影响.分析了吸收层厚度与吸收长度、扩散长度之间的联系,获得了设计最佳吸收层厚度的经验公式.研究结果显示入射光波长超过截止波长时,响应率随吸收层厚度增加单调增加,并逐渐饱和.响应率峰值对应的波长随吸收层厚度增加,有向长波偏移的趋势.最佳吸收层厚度值随少子寿命或入射光波长的增大而增大.同时,研究了衬底、钝化层与HgCdTe材料之间异质界面电荷对光响应率的影响,发现正的界面电荷在衬底异质结界面处形成诱导pn结,对响应率影响显著.采用金属-氧化物-半导体二极管模型,分析了其中的内在物理机理,并获得了降低其影响的优化方案.The effects of absorption layer parameters and hetero-interface charge on photoresponse of long-wavelength HgCdTe photodiode have been studied. The correlations between thickness of absorption layer and absorption length and diffusion length are investigated. An empirical formula is proposed to estimate the optimal thickness of absorption layer. Our theoretical investigations indicate that, when the wavelength of incident light is longer than the cut-off wavelength, the photoresponse monotonically increases with the increase of absorption layer thickness, and saturates subsequently. The wavelength of the maximal photoresponse increases with the increase of absorption layer thickness, and tends to shift toward long wavelength region. The optimal absorption layer thickness increases with increasing minority carrier life time and wavelength of incident light. It is found that the positive interface charge can induce a p-n junction at the substrate interface and significantly reduce the photoresponse. By using the metal-oxide-semiconductor diode model, possible physics mechanisms are investigated, and an approach is proposed to reduce the effects of hetero-interface charge on the photoresponse.

关 键 词：长波HgCdTe器件 光伏型红外探测器 光响应率 少子寿命 

分 类 号：TN215[电子电信—物理电子学] TN304.207