基于栅控石墨烯纳米带阵列的室温太赫兹宽带探测器

In an increasingly complex domestic and international situation, the demands for portable terahertz imaging/spectroscopy system are more and more urgent. Miniaturization, high sensitivity, wide bandwidth and being work in room temperature are continuing trends for micro terahertz system. The direct THz detection technologies based on thermo sensitive，plasma wave and photon detection are the important methods to realize a miniaturized and high-sensitive THz detector. But these detectors are restricted in application currently owing to the deficiencies in operating temperature, response bandwidth and response speed, etc. This project aims at a broadband THz detector with high sensitivity at room temperature. This project will research the dual regulation of the graphene layers bandgap adopting lateral restraint and vertical electric field, explore the physical mechanism of interaction of THz wave and graphene, systemically research the methods of modeling and design of the THz detector based on gated graphene nanoribbons, for achieving the expansion of frequency band. A new process adopting nanowires mask is proposed to manufacture the graphene nanoribbons，and the prototype of THz detector based on gated graphene nanoribbons would be manufactured and tested for validation of the proposed model. This project can provide important theory foundations and technologies support for the integrated design and efficiently low-cost fabrication of high-sensitive, rapid and miniature THz wideband detector under room temperature.

在日益复杂的国内外形势下，反恐、安检、缉毒等领域对便携式太赫兹成像/光谱系统需求日益迫切。太赫兹系统微小型化对探测器提出了微型化、高灵敏度、宽带、室温工作等更高要求。基于热原理、等离子体波和光子探测原理的直接THz探测技术是实现THz探测微型化、高灵敏的重要途径；但这些探测技术分别在工作温度、响应带宽和响应速度等方面仍存在不足，在诸多应用中受限。本项目以高灵敏、高速室温THz宽带探测器为对象，以侧向限制与垂直电场作用下双层石墨烯的能隙双重调控机制的研究为切入点，探索太赫兹波与石墨烯相互作用的物理机制，系统研究基于栅控石墨烯纳米带的THz探测器的建模及设计方法，突破带宽拓展技术；提出以纳米线为掩模的石墨烯纳米带阵列加工方法，研制基于栅控石墨烯纳米带阵列的室温THz宽带探测器原理样品，完成模型验证；为灵敏度高、响应快的微型室温THz宽带探测器的集成设计与低成本高效制造奠定重要的理论和技术支撑。

针对现有太赫兹探测器在工作温度、响应带宽和响应速度等方面存在的不足，本项目提出开展石墨烯太赫兹探测技术的研究。提出了基于光电导效应的石墨烯纳米带探测器新结构，研究了栅控石墨烯纳米带的太赫兹响应机理，建立了栅控石墨烯纳米带光电导太赫兹探测模型，基于栅压扫描实现探测器带宽拓展，优化了探测器结构参数。提出了纳米结构的边沿缺陷假设，很好解释了石墨烯纳米能隙测试结果与理论计算存在较大偏差的原因；研究了石墨烯等离激元产生机理，基于石墨烯纳米网格的太赫兹FET宽带探测理论模型，采用FDTD软件对基于等离激元的石墨烯太赫兹探测器进行了仿真分析，形成了太赫兹探测器的设计方法。研究了太赫兹探测器集成加工关键技术，解决了高精度石墨烯纳米网格加工难题，制作出了石墨烯纳米结构太赫兹探测器原理样品；针对探测器有效面积小，光能利用率低的问题，设计制作出了太赫兹超衍射聚焦平面透镜，显著提高了太赫兹波耦合效率；搭建了太赫兹探测器测试系统，验证了石墨烯纳米结构的电子结构的理论计算结果，测得室温下探测器响应度约为9.89e2A/W，并实现了对小金属件的太赫兹成像实验验证。为促进微型化室温高灵敏太赫兹探测器阵列的研制和应用奠定了重要的理论和技术基础。