甚长波量子阱红外探测器的暗电流特性研究  

Study of the dark current in very long wavelength quantum well infrared photodetectors

作　　者：熊大元[1] 李宁[1] 徐文兰[2] 甄红楼[1] 李志锋[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 [2]华东师范大学信息科学技术学院,上海200062

出　　处：《物理学报》2007年第9期5424-5428,共5页Acta Physica Sinica

基　　金：国家自然科学基金重点项目(批准号:10234040);国家自然科学基金(批准号:60476031;10474020;10474108)资助的课题.~~

摘　　要：基于载流子在量子结构中的输运理论研究了甚长波量子阱红外探测器(峰值响应波长15μm,量子阱个数大于40)的载流子的输运性质.研究结果表明,在甚长波量子阱红外探测器中,电流密度一般很低,暗电流主要来源于能量高于势垒边的热激发电子.通过薛定谔方程和泊松方程以及电流的连续性方程的自洽求解,发现外加偏压下电子浓度在甚长波器件各量子阱的分布发生较大变化,电场在整个器件结构上呈非均匀分布,靠近发射极层的势垒承担的电压远远高于均匀分布的情形.平带模型假定电压在器件体系上均匀分布,导致小偏压下的理论计算值远远低于实验值.通过自洽计算获得电子浓度及电场强度在整个器件结构上的重新分布,由此获得的暗电流特性很好地解释了实验结果.A study of the carrier transport performance of GaAs/AlGaAs very long wavelength quantum well infrared photodetectors （peak wavelength： 15 μm; period： 〉40） has been carried out based on quantum wave transport theory. It was shown that the thermoexcitation effect dominates in the devices. By the current continuity and self-consistent calculation based on Schrdinger equation and Poisson equation, we found that the main feature resulting from the model is the redistribution of the carriers and the electric field along the whole structure being made uneven to maintain current conservation. The high-field region extends over a few barriers near the emitter contact, which takes up a considerable part of the applied voltage. The conventional flat band model assumes that the applied voltage drops linearly across the structure, leading to the numerical value of dark current to be far from the experiments, especially at small bias. The numerical result of self-consistent calculation well explains the measurement data.

关 键 词：甚长波量子阱红外探测器 量子波输运 暗电流 

分 类 号：TN215[电子电信—物理电子学]