石墨烯纳米带载流子迁移率的多尺度理论研究

项目名称： 石墨烯纳米带载流子迁移率的多尺度理论研究

项目编号： No.21203127

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 物理化学

项目作者： 王果

作者单位： 首都师范大学

项目金额： 22万元

中文摘要： 电子器件的载流子迁移率和载流子类型直接影响其速度和性质，石墨烯纳米带具有非零的带隔和高的载流子迁移率因而可能成为新型高性能电子器件。在电极连接的石墨烯纳米带电子器件中，空穴和电子本征载流子迁移率的相对大小对于实际器件设计成p型或者n型以及器件的操作都是十分重要的。本项目基于形变势理论和非平衡态格林函数方法分别研究石墨烯纳米带宏观材料和微观电子器件两种尺度下的载流子迁移率，探究边缘不光滑、边缘氢原子以及声子对体系性能的影响。通过晶体轨道分析，得出结构上的变化对体系载流子有效质量和形变势的影响趋势，进而提出调节载流子迁移率大小的方法。从电声耦合密度的概念出发，通过直观的图形分析电子传输过程中体系各部分电子密度的变化与声子模式的匹配程度，提出调节电声耦合强度的手段，最终阐明石墨烯纳米带电子器件中空穴和电子迁移率的相对大小，并为提高其性能提供结构上的途径。

中文关键词： 石墨烯纳米带；载流子迁移率；密度泛函理论；形变势理论；电流—电压特性

英文摘要： Carrier mobilities and carrier types directly affect the speed and properties of electronic devices. Graphene nanoribbons could be a new type of high-performance electronic devices because of their non-zero band gaps and high carrier mobilities. In graphene nanoribbon-based electronic devices, the relative magnitude of intrinsic carrier mobilities for holes and electrons is important to the design and operation of the devices, which can be p-type or n-type. In this project, a multi-scale theoretical investigation on the graphene nanoribbons both in macro-materials and micro-electronic devices is performed based on deformation potential theory and non-equilibrium Green's function method. The effect of edge roughness, edge-hydrogens as well as phonons on the carrier mobilities is systematically studied. The influence coming from the structural change on the carrier effective mass and deformation potential can be obtained by using crystal orbital analysis, which is useful for giving a way for adjusting the carrier mobilities. When the change of electron density in the transport process and the vibration are both strong at the same area in the system, the vibronic coupling density is large. It is crucial for elucidating the relative magnitude of carrier mobilities for holes and electrons in graphene nanoribbons, and

英文关键词： graphene nanoribbon；carrier mobility；density functional theory；deformation potential theory；I-V characteristics