应力调控无序边缘石墨烯纳米带物性的理论研究

Graphene has recently raised extensive interest of the world-wide scientific community since it has been obtained successfully in 2004. Generally, strain can produce the regularity modulation of the electrical properties of graphene nanoribbons (GNRs). However, The preparation of armchair-edge GNR still has many obstacles and difficulties. The challenging problems, therefore, are to precisely control of the disorder edge and elucidate its impact on the physical properties and device performance. In this research project, the modulation of electronic structure and electrical transport properties is investigated for GNRs with the chiral parameter determined edge disorder, using the calculation and simulation of density functional theory and non-equilibrium Green’s function. Furthermore, the band structure, density of states, charge density and electronic transport properties in response to the external tensile strain and the edge structure of graphene nanoribbon may be discovered and revealed. Moreover, the impact of the GNRs length to electronic transport properties of nano-devices should be discussed. The project is closely associated with the processing and preparation of graphene device. It has potential to find application in nano-electromechanical system (NEMS) and has important theoretical and practical significance.

石墨烯自发现以来引起了世界范围内广大科学研究团体的广泛兴趣。通常应变能够对石墨烯纳米带的电学特性产生规律性的调控，但是目前对石墨烯纳米带边缘结构的精确控制仍然是有待进一步解决的挑战性问题。本项目结合密度泛函理论和非平衡格林函数电子输运计算，在深入研究由手性参数决定的石墨烯纳米带无序边缘结构对其电子结构和输运特性影响的基础上，进一步探索应变条件下无序边缘结构对能带结构、态密度、电荷密度及电输运特性产生的影响，进而发现和揭示无序边缘石墨烯纳米带及其物性对外加拉伸应变产生响应的机理，并讨论带长对实际器件电输运特性影响。本项目密切地关联石墨烯器件的加工制备技术，面向石墨烯在纳机电系统中的潜在实际应用，具有重要的理论和实际应用的意义。

石墨烯自发现以来引起了世界范围内广大科学研究团体的广泛兴趣。通常应变能够对石墨烯纳米带的电学特性产生规律性的调控，但是目前对石墨烯纳米带边缘结构的精确控制仍然是有待进一步解决的挑战性问题。本项目结合密度泛函理论和非平衡格林函数电子输运计算，系统地研究了石墨烯纳米带无序边缘结构对其电子结构和输运特性影响。计算发现带宽较窄的扶手椅型石墨烯纳米带的发现费米能级附近导带和价带在拉伸应变下出现附带宽的增加而消失的非对称的带隙调制行为。此外，对不同的边缘比例的石墨烯纳米带电子结构及输运特性的研究提出其随拉伸应变变化的模式与带宽有着紧密的关联，并且发现带宽参数为9的无序边缘结构石墨烯纳米带出现由拉伸应变调控的负微分电阻现象。本项目密切地关联石墨烯器件的加工制备技术，面向石墨烯在纳机电系统中的潜在实际应用，具有重要的理论和实际应用的意义。