基于光场调控深亚波长结构集成的二维材料光电耦合增强机理与探测应用

2D materials with nano- and micro-structures could control the flow of light through field manipulation, leading to a series of new physical effects and promising applications, and thus attract a lot of attention all over the world. However, serving as infrared photodetectors, 2D materials are faced with low absorption efficiency and large dark current. In this project, we propose to integrate plasmonic resonant cavities with 2D materials to overcome the two bottleneck problems. The investigation would be mainly focused on new effects, new mechanisms and new techniques in the area of interaction between matters and manipulated light field. In detail, we would study absorption enhancement of 2D materials by deep sub-wavelength localized light field manipulation; influence of 2D materials on the photonic modes of the composite structure; intrinsic dark current control based on plasmonic light coupling; polarization dependent excitation of the photonic modes of anisotropic plasmonic resonant cavities and the polarization discriminative photoresponse of the 2D materials in the composite structure. By solving the above scientific problems, we propose to expound the mechanism of absorption enhancement of the 2D materials by resonant excitation of a deep sub-wavelength localized light field, find out the rule of efficient polarization discriminative photoresoponse of the 2D materials by resonant excitation of the polarization sensitive photonic modes, reveal the role of the relative orientation between the 2D material and the anisotropic plasmonic resonant cavity in manipulating the polarization discriminative detection ability, and finally achieve the prototype plasmonic resonant cavity integrated 2D material infrared photodetectors with enhanced photoresponse and enhanced polarization resolving performance. This project would pave the way for new-type high-performance 2D material infrared photodetectors as a scientific base.

光场调控的二维材料纳微结构能够控制光的流动，带来了一系列新颖物理效应和应用前景，引起了国际学术界的关注，但是，作为红外光电探测器件面临着吸收效率低和暗电流大的关键科学问题。本项目聚焦光场调控与物质相互作用的新效应、新机理、新技术，针对二维材料光吸收低和暗电流大的瓶颈，以等离激元共振腔-二维材料复合结构为对象，通过研究深亚波长局域光场调控的二维材料光吸收增强机理，探索二维材料对光子模式的影响，建立等离激元的二维材料本征暗电流抑制方法，解决光子模式的偏振选择激发及二维材料偏振调控等科学问题，阐明基于深亚波长局域光场共振激发的二维材料光吸收增强原理，获得基于光子模式偏振选择激发的二维材料高效偏振辨别光响应新思路，揭示二维材料与共振腔相对取向对于偏振辨别响应能力的调控规律，完成原理性红外探测器件，实现二维材料光电响应和偏振辨别探测能力的提升，为新型的高性能二维材料红外探测器件的发展提供科学基础。

二维材料因其独特的光学和光电性质在光电探测领域受到了广泛关注。在微纳光学结构的光场调控下，二维材料的光电耦合和探测性能将被进一步提高。本项目按照预定的研究计划，开展了相关的理论和实验研究。探索了深亚波长局域光学模式的激发特性，构建了二维材料红外波段的电磁响应模型，包括有效折射率、光电导率、色散性质、掺杂浓度等物理特性，提出了等离激元共振腔集成的二维材料探测器结构。通过有限元仿真获得了等离激元共振腔集成二维材料复合结构的透反射光谱、模式属性、光场强度和极化分布等信息，验证了等离激元光学模式共振增强的局域光场可有效提高二维材料的光电耦合。以石墨烯为例，揭示了微纳结构的光场调控对于光耦合增强的机制，并推广到其它二维材料中。等离激元共振腔集成的二维材料红外探测器体现了光子-电子联合调控的思想，通过金属反射面静电栅控调节二维材料的费米面，不仅改善了光吸收，同时也改变了材料载流子浓度，实现了光电耦合效率的提高。通过偏振选择性激发的原理，获得了偏振选择性激发的光子模式的具体结构参数，发展了增强二维材料偏振响应的方法，获得了高偏振选择性的器件。研究了二维材料各向异性光电流随波长变化的规律。发展了二维材料生长、转移，以及微纳结构制备的方法，走通了微纳结构集成的二维材料探测器的工艺路线，实现了集成等离激元共振腔的二维材料探测器原型器件。搭建了自动化的宽波段红外偏振分辨的光谱-光电测量系统，实现了稳定的空间和偏振控制。验证了高偏振消光比、高响应率的微纳光学结构集成的二维材料红外探测器。发表标注本项目支持的SCI论文51篇，发表期刊包括Nat. Commun.、Sci. Adv.、Light.: Sci. Appl.、ACS Nano等国际知名期刊；申请发明专利7项；完成了各项预期指标要求。项目负责人获得2020年上海市技术发明一等奖。2名团队成员获得2021年优秀青年科学基金项目，1名团队成员入选中国科协青年人才托举工程，1名博士后入选2021年上海市超级博士后激励计划，3名研究生在研究生创新论坛上获奖。