新型非制冷中波红外带间级联探测器研究

Aiming at the applications of high performance cooling-free infrared detectors in aerospace, military, medical diagnosis and security, in this project, we propose to carry out studies on interband cascade infrared photodetectors (ICIP), a cutting-edge research topic in the world. Through fine quantum designs, we will force electrons and holes to follow in one but opposite direction, respectively and to generate photovoltaic effects in an ICIP. In this way, we will eliminate space charge regions in traditional PN junctions and the associated diffusion currents in an ICIP which hinders a photodiode work at a room temperature. In addition, we will cascades several superlattice absorption regions to significantly reduce the effects of low diffusion length at room temperature on device performances. In the project, we will carry out material growth, especially interband cascade structures on InAs substrates, a novel idea proposed first by us in the world, as well as device fabrication and characterization. We will study the quantum process in the ICIPs, such as infrared absorption and emission, resonant tunneling and phonon assisted scattering, understand the basic properties of the ICIP materials and their effects on ICIP device performances. We will achieve high performance ICIP single element mid infrared devices which will operate well at room temperature without cooling and achieve a maximum operation temperature of 400K. By achieving the above goals, we would like to explore new directions for the development of cooling-free infrared photodetectors.

围绕我国航天、国防、医疗、安防等领域对高性能非制冷红外探测器的迫切需求，本项目开展国际前沿的新型带间级联红外探测器研究。通过精巧的量子设计，促使光生电子和空穴在器件纵向结构内各自反方向运动，以产生光伏效应，消除传统PN结的空间电荷区及由此产生的扩散电流对光伏型红外探测器室温工作的阻碍；引入级联概念，优化各分段的红外吸收区结构，克服传统PN结红外探测器室温下因少子扩散长度小而引起的量子效率低的弱点。系统开展带间级联材料，特别是原创的InAs基带间级联探测材料的外延生长机理以及器件制备与性能表征等各项研究；深入认知带间级联结构内的吸收与辐射跃迁、共振隧穿和声子散射等量子过程及其对器件光电性能影响。在此基础上，获得基于带间级联结构的光伏型非制冷中波红外探测器，最高工作温度达到400K，突破传统光伏型中波红外探测器难于室温工作的瓶颈，为我国非制冷红外探测器的发展开拓新的前沿和方向。

围绕我国航天、国防、医疗、安防等领域对高性能非制冷红外探测器的迫切需求，本项目开展国际前沿的新型带间级联红外探测器研究。通过精巧的量子设计，促使光生电子和空穴在 器件纵向结构内各自反方向运动，以产生光伏效应，消除传统PN结的空间电荷区及由此产生的 扩散电流对光伏型红外探测器室温工作的阻碍；引入级联概念，优化各分段的红外吸收区结构，克服传统PN结红外探测器室温下因少子扩散长度小而引起的量子效率低的弱点。系统开展带间级联材料，特别是原创的InAs基带间级联探测材料的外延生长机理以及器件制备与性能表征等各项研究；深入认知带间级联结构内的吸收与辐射跃迁、共振隧穿和声子散射等量子过程及其对器件光电性能影响。.在本项目研究中，成功在InAs衬底上外延生长了高质量带间级联探测材料，通过透射电子显微镜对材料的界面组分和应变信息进行了分析，计算了超晶格吸收区的有效带隙、带边位置，以及弛豫区和隧穿区的能级位置，分析结果与实验结果相吻合，由此对结构进行了优化设计。设计中考虑了多级级联在不同工作温度下对响应率、暗电流以及探测率的影响。针对室温工作，设计并获得了基于10级带间级联结构的光伏型非制冷中波红外探测器，在327K温度下获得清晰响应光谱，响应截止波长达到5.5微米，室温下峰值探测率达到4.7×109 cm·Hz1/2/W；该器件进行了背入射结构设计，并采用了非制冷TO封装。在此基础上，利用干法刻蚀技术实现了320×256规模的台面型带间级联红外焦平面原型器件，焦平面测试结果表明，其在80-120K范围内量子效率达到30%，135K下噪声等效温差为34.3mK，盲元率为0.29%，获得了清晰的成像演示。.本项目的研究突破了传统光伏型中波红外探测器难于室温工作的瓶颈，为我国非制冷红外探测器的发展开拓新的前沿和方向。