量子点红外探测器材料及器件物理研究

Infrared photodetectors are of great importance in the civil and military fields. Thus, high-performance infrared photodetectors, especiall thoese working in the long and the very long wavelength ranges,are prohibited from selling to China by the west countries. This application intends to investigate the physics, material growth and device fabrication of the quantum dot infrared photodetectors (QDIPs) based on III-V materials. The purpose is to investigate the physics machanism of enhancing the device performance witout fabricating the surface gratings and to overcome the drawbacks of the low working tempearture and no absorption under normal incidence irraduation of quantum well infrared photodetector. The studies of this application empass the material growth of InAs and GaSb quantum dots by controlling the dot shape to enhance the lateral quantum confinement and consequently to increase the intersubband absorption efficiency under normal incidence irradiation. We will study how to control the detection wavelength of QDIP by controlling the dot size, shape, composition, and the strain status. We will also investigate new device structures that may increase the carrier lifetime to enhance the performance of long and very long wavelength QDIP and will make use of the tunneling structure to decrease the dark current.

红外探测器在民用与国家安全领域有非常重要的意义，因此好性能的红外探测器尤其是长波及甚长波红外探测器国外对我国是严格禁运的。本项目以III-V族材料为基础，开展半导体量子点红外探测器(quantum dot infrared photodetector QDIP)相关的物理、材料生长及器件制备的研究，力争使得器件既能在不制作表面光栅的情况下工作，同时探索提高器件性能的物理机制，弥补量子阱红外探测器不能在正入射下工作和最佳工作温度低的缺点。本项目主要研究InAs及GaSb高均匀性量子点探测器材料的制备技术；研究控制量子点的形状，增强横向量子限制效应，来提高垂直入射下的子带吸收效率；研究通过控制量子点的大小、形状、组分以及应变状态来控制量子点中子带跃迁的探测波长；提出利用隧穿结构来降低暗电流、提高载流子寿命的新型器件结构，从而提高长波及甚长波红外探测器的器件性能。

本项目主要研究InAs及GaSb高均匀性量子点探测器及激光器材料的制备技术；研究控制量子点的形状，增强横向量子限制效应，来提高垂直入射下的子带吸收效率；研究通过控制量子点的大小、形状、组分以及应变状态来控制量子点中子带跃迁的探测波长；提出利用量子隧穿结构来降低暗电流、提高载流子寿命的新型器件结构，从而提高长波及甚长波红外探测器的器件性能, 此项目也探索在 GaAs基实现长波长发光的物理途径。目前，标注本项目的文章已经发表的有11篇，包括三篇发表在Applied Physics Letters上，两篇发表在IEEE Electron Device Letters上，两篇发表在IEEE Photonics Technology Letters上。.两个典型的结果：.1,，在GaAs基衬底上生长出的InAs量子结构实现了光荧光发射波长大于1.9微米，为GaAs基长波器件奠定了基础，这是GaAs基目前所能实现的最长波长.2，采用分子束外延技术制备了三色InAs/GaAs 量子点红外探测器。 器件采用nin 型结构, 在GaAs(001) 衬底上制备了点在阱中 (dots-in-a-well, DWELL) 结构红外探测器，器件在77 K 下的红外光电流谱有三个峰值: 6.3, 10.2 和11微米，并分析了它们的跃迁物理机制。