肖特基红外热电子光电探测机理与关键技术研究

Infrared photodetections have very extensive applications in military, aerospace and civilian uses. At present, the most widely used photodetectors are based on the semiconductor quantum-well or quantum-dot structures. However, such devices are complex and costly in fabrication and require extremely-low-temperature refrigeration. Exploring new types of infrared photodetection technologies with the characteristics of simple and room-temperature operation is an important way to realize the highly efficient, compact, and low-cost infrared photodetectors. In this project, with introducing the hot-electron photoconversion mechanism and the plasmonic/surface-wave optical resonances to target the infrared (especially mid-infrared) spectral band, we study the nanowire (nanohole) array and planar multi-layer structure with Schottky electrical configuration to manipulate the incident light field and intrinsic carrier behaviors, in order to realize the infrared hot-electron photodetector with high absorption and high photoresponsivity. In this project, we will extensively study the impedance-match by nanowire (nanohole) array, Tamm plasmons, optical surface waves, and optical interference by ultra-thin film in order to achieve the highly tunable narrowband (broadband) infrared photodetectors. Based on the fundamental physics and quantum optics, the project will study the internal electromagnetic characteristics and the detailed generation, transport, recombination, and collection processes of hot electrons, investigate the scientific principles, and realize the optimal designs of the optoelectronic performance. Finally, the preparation, characterization, and photoelectric measurement of proposed devices will be conducted. This project is expected to provide new technical options for infrared photodetections and it will promote the development of the non- refrigeration infrared photodetection technologies.

红外光探测在军事、航天和民用等领域应用广泛。目前为止，多采用量子阱甚至量子点等结构进行红外探测，但其工艺复杂、成本高，且需超低温制冷运行。研究结构简单、室温工作的红外光探测新技术是实现高效能、轻便化和低成本的重要途径。本课题引入基于肖特基结和表面等离子/表面波共振的热电子光电转换机制，针对红外（尤其中红外）波段，研究利用肖特基结纳米线（孔）阵列和平面结构实现对入射光场和载流子行为的精确调控和优化，实现高吸收、高响应度非制冷红外光电探测。课题系统研究纳米线（孔）阵列导纳匹配、Tamm等离子、光学表面波和超薄介质膜共振等机制，设计针对红外波段可调的窄（宽）带光电探测。课题从基本物理光学、量子力学入手，研究系统内在电磁特征和热电子产生、输运、湮灭和收集等微观过程，解析科学原理、实现光电性能的优化调控，并开展制备、表征和测试。本课题可为红外光电探测提供新颖技术手段，推动非制冷红外探测技术的发展。

本课题研究的肖特基红外热电子光电探测器通过金属与半导体接触形成的肖特基结来收集金属吸收光子后产生的高能量热载流子，拓展了传统半导体光电探测器的可探测波长范围。然而，较低的热电子光电转换效率和复杂的金属微纳结构导致器件成本高和难以大面积制备等问题，阻碍了热电子红外光电探测器的实际应用。本研究基于第一性原理计算和蒙特卡罗模拟，研究了二维层状过渡金属碳、氮化物在热电子器件中的应用；研究了不同应变对金属电子结构的调控和对热载流子产生、传输性能的影响；探索了热电子和热空穴器件的热力学损耗分析和性能极限；在基于等离激元纳米结构的热电子光电探测器理论和研究方面：提出并制备了基于金属纳米圆柱阵列、纳米孔和纳米碗阵列结构的热电子光电探测器，实现了超宽带、偏振不敏感的广角高吸收和热电子光电探测。在基于平面结构的热电子光电探测器方面，提出包括将塔姆等离子和双腔结构引入到热电子光电转换中，不仅简化了器件结构，还获得了更高的热电子光电转换性能。进一步地从理论和实验上验证了一个简单的平面双层系统就可以实现光学完美吸收，并探讨了双层系统在宽带热载流子光电探测中的应用。最后对热载流子光电探测研究的三个重要方面进行了详细介绍和展望，包括金属微纳结构中的热载流子产生、传输和注入过程；热载流子器件的热力学损耗分析以及新材料、新结构实现器件性能的突破；热载流子光电探测器在纳米显微成像、圆偏振光检测和折射率传感等领域的应用。