基于平面多层结构的热电子光电转换理论与器件研究

Surface-plasmon-based hot-electron photoconversion and photodetection are hot research topics in recent years, due to the benefits of high energy localization, high tunability, and the ability of breaking the limitation of semiconductor bandgaps for infrared or longer-wavelength photodetections. However, the conventional systems are usually composed by the complicated micro-nano structures, with a high fabrication complexity and a high cost. In this project, we propose the simplified hot-electron photoconversion systems composed solely by multiple planar films by deeply exploiting the planar resonant mechanisms and structures. By doing so, the system configuration can be significantly simplified and simultaneously the photoconversion performance can be improved. Based on the core MIM (metal-insulator-metal) structure of hot-electron photoconversion, the new cavities with TAMM surface state and micro-cavity resonances are introduced. Through modulating the photonic crystal properties of the multi-planar-film system, the efficient, narrow-band, and wide-angle harvesting of the incident photon energy can be realized. We further establish the comprehensive mathematical, physical and simulation models for the new system to mimic the generation, transportation, dissipation, and collection procedures of the hot electrons, in order to predict and optimize the optical absorption and photoconversion performance of the system. Finally, the fabrication, characterization, and testing of the designed photoconversion devices are performed, in order to find the stable and simplified fabrication schemes. The successful implementation of this project can promote the understanding of the basic mechanisms of hot-electron photoconversion devices as well as contribute the novel designs and fabrications of these devices.

基于表面等离子微纳调控的热电子光电转换与探测是近年研究热点，它具备极强的能量局域和谐振可调性，可突破传统半导体禁带限制实现红外甚至更远波段的光电转换。然而，复杂的微纳结构往往使系统制备困难、工艺成本高。本项目通过深入挖掘平面谐振机制和结构，构建多层平面结构热电子光电转换系统，在简化系统的同时提升光电转换性能。项目将在MIM（金属-绝缘体-金属）热电子光电转换结构的基础上，引入TAMM表面态和微谐振腔等平面结构，通过调控平面多层系统的光子晶体能带属性，实现对入射光子能量的高效、窄带和广角局域。进一步地，构建完整的热电子产生、输运、湮灭和收集过程的严格数学、物理和仿真模型，理清这些微观行为的物理成因，预测并优化系统的吸收和光电转换性能。在此基础上，开展器件制备、表征和光电性能测试，探索稳定、易行的制备工艺手段和流程。本项目的成功实施可促进对热电子光电转换机制的理解，获得新颖的设计制备方案。

热电子光电转换与探测是近年研究热点，它具备极强的能量局域和谐振可调性，可突破传统半导体禁带限制实现红外甚至更远波段的光电转换。然而，复杂的微纳结构往往使系统制备困难、工艺成本高。本项目通过深入挖掘平面谐振机制和结构，构建了多层平面结构热电子光电转换系统，在简化系统的同时提升了光电转换性能。项目在MIM（金属-绝缘体-金属）热电子光电转换结构的基础上，引入TAMM表面态和微谐振腔等平面结构，通过调控平面多层系统的光子晶体能带属性，实现了对入射光子能量的高效、窄带和广角局域。其中，提出的超薄膜双势垒系统可达152.9 mA/W的响应度和60％的外量子效率，相对于常规系统提高了近两个数量级。进一步地，构建了完整的热电子产生、输运、湮灭和收集过程的严格数学、物理和仿真模型，理清了这些微观行为的物理成因，预测并优化了系统的吸收和光电转换性能。在此基础上，开展了器件制备、表征和光电性能测试，探索稳定、易行的制备工艺手段和流程。本项目促进了对热电子光电转换机制的理解，获得了一系列新颖的设计和制备方案，为热电子光电探测奠定了重要的理论和实验基础。