碳纳米管–金属异质结的太赫兹波段响应特性研究

In recent years, terahertz detection has achieved considerable progress, but it remains a key factor to overcome the bottleneck of applications of terahertz technology in real world. Due to the unique electrical and optical properties, nanostructured materials are expected to provide new opportunities for the development of terahertz detection techniques. This project considers the design, fabrication and response characteristics of heterodimensional heterostructured devices formed by carbon nanotubes and bulk metal materials in the terahertz range. We will focus on the investigation on the interaction of terahertz radiation with the heterojunction, make a deep understanding of the electron transport behavior in the heterojunction under terahertz illumination, and reveal the generation mechanisms of photocurrent, photovoltaic, and photoconductive effects. We will test and analyze the terahertz response characteristics and rules of the heterojunctions with different structures under different excitation conditions and working environments, and explore the key factors affecting the response sensitivity and speed of the heterojunction. On the basis of these theoretical and experimental investigations in comprehensive and systematic ways, we will optimize the design and fabrication of the device from the perspective of improving the terahertz response performance, and construct a novel and efficient carbon nanotube–metal heterojunction based terahertz detector prototype device, so as to provide a new way for the development of high-performance and practical terahertz detection techniques.

近年来，太赫兹探测技术已经取得长足进展，但仍然是突破太赫兹技术应用瓶颈的一个关键因素。纳米结构材料由于具有独特的电学和光学性质，有望为太赫兹探测技术的发展提供新的机遇。本项目选择由碳纳米管和金属体材料形成的“异维异质”结构器件的设计、制备及其在太赫兹波段的响应特性为研究内容，重点探讨太赫兹辐射与异质结的相互作用过程，深刻理解太赫兹场作用下异质结中的电子输运行为，揭示光致电流、光生伏特和光电导效应的产生机理；测试分析不同器件结构、不同激发条件和不同工作环境下异质结的太赫兹响应特性及规律，深入挖掘影响异质结响应灵敏度和速度的关键物理因素。在全面系统地理论与实验探究基础上，从改善太赫兹响应性能角度优化器件的设计与制备，构建出基于碳纳米管–金属异质结的新型、有效的太赫兹探测器件原型，为发展高性能、实用化的太赫兹探测技术提供新途径。

太赫兹探测是是突破太赫兹技术应用瓶颈的一个关键因素。碳纳米材料（包括碳纳米管、石墨烯）因为具有独特的电子学和光学性质，有望为太赫兹探测技术的发展提供新的机遇。本报告总结了在国家自然科学基金青年基金项目（编号11404182）支持下所开展的有关碳纳米管、石墨烯与金属接触结构太赫兹响应特性方面研究的进展。首次研究发现了碳纳米管束-金属异质结构、石墨烯-金属异质结构在太赫兹波激发下存在显著的光响应，并深入研究了响应的物理机理，证实了其为光热电效应。该类结构形成的探测器件具有室温工作、宽带响应、低功耗、结构简单、易于集成等优点，为太赫兹探测提供了一种新途径。