基于铟砷锑窄禁带半导体器件的太赫兹探测机理研究

The detection of Terahertz wave is a major focus in the field of terahertz technology. It is of great importance to develop terahertz detector that is fast responding, highly sensitive and workable at near room temperature (RT). In recent years, our group has developed mercury-cadmium-telluride (MCT) detector. Sensitive terahertz detection has been achieved, which is based on the phenomenon that the conductance of the device can be manipulated by accumulating electrons from the metals in the electromagnetic induced well. InAs1-xSbx is an excellent III-V compound semiconductor with matured applications in infrared detection, which has the minimal and adjustable bandgap, stable structure and high carrier mobility. To further discuss the terahertz detection mechanism of metal-semiconductor-metal structured device, and develop highly sensitive terahertz detector, this project would carry out the researches based on InAs1-xSbx materials in the following topics: study the influence of varied temperature and material parameters on the performance of InAs1-xSbx detectors, as well as the detection mechanisms relating to the generation and recombination process of carriers; study the contribution of hot carrier effect and thermal effect related to lattice vibration to the performance of the device; measure and improve the performance of the device experimentally, develop InAs1-xSbx terahertz detectors that is fast responding, highly sensitive and workable at near RT. This project is able to provide important technical support to basic research in terahertz, terahertz imaging and space remote sensing.

太赫兹波的探测是太赫兹技术领域的重要内容之一。发展响应速度快、工作灵敏度高、可近室温工作的太赫兹探测器具有重大应用价值。近年来，课题组发展了碲镉汞太赫兹探测器。利用电磁辐射诱导势阱束缚载流子实现器件电导变化的新现象，实现了对太赫兹波的高灵敏度室温光电探测。铟砷锑是一种在红外探测方面有成熟应用的半导体材料，具有III-V族半导体最小且易于调节的带隙、迁移率高、结构稳定。为深入探讨金属-半导体-金属结构器件的太赫兹探测机理，以及发展高灵敏度太赫兹探测器，本申请项目将以铟砷锑为基础，开展以下研究：研究变温条件、材料物理参数对铟砷锑器件探测性能的影响，以及载流子的产生复合过程和探测机理；研究热载流子效应、晶格热效应对器件性能的贡献；实验验证并优化器件性能，发展出高灵敏度、快速响应、可近室温工作的铟砷锑太赫兹探测器件。本研究可为太赫兹基础研究及未来太赫兹成像、航天遥感等应用领域提供重要技术支持。

发展响应速度快、工作灵敏度高、可近室温工作的太赫兹探测机理具有重要科学意义和应用价值。本项目以锑化铟、铟镓砷、锰钴镍氧等材料为基础，构筑金属-半导体-金属结构太赫兹探测器，并对器件探测机理与优化方法开展了以下研究：首先，研究了铟砷锑材料的光学、电学性质，分析了器件性能与载流子浓度、迁移率之间依赖关系的探测机理。发现器件响应率与载流子浓度成反比，而响应速度与材料迁移率正相关，与电磁诱导势阱效应理论公式预计一致。然后，探讨表面等离激元、外部耦合天线、热效应对探测器件性能的贡献。锑化铟材料中表面等离激元频率在太赫兹波段，入射太赫兹波将通过外部耦合天线增强作用，在半导体-金属电极交界位置产生非平衡载流子，贡献光电流，实现器件峰值响应增强。比较多种不同衬底热导金属-半导体-金属结构器件探测性能，其时间常数与热导成反比，证明可能存在热效应贡献。进一步的，通过设计不同沟道尺寸和耦合天线，在实验上实现器件探测性能优化，制备出噪声等效功率小于10 pW/Hz0.5，响应时间微秒量级的高灵敏线列探测器；基于新器件进行了成像应用验证。.研究工作指出了未来工作思路：一方面，电磁诱导势阱效应既不会向外发射光子，也没有电子电离，无法直接观察该现象，需通过对微区载流子浓度分布进行高精度测定，以对此现象进行间接观察。另一方面，器件响应率和响应速度与器件沟道尺寸成反比，这要求尽可能减小器件沟道；但小的器件沟道将使入射太赫兹波大部分损失，为解决此矛盾，探测元需设计为多元阵列结构。