Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL 32611, USA.
ACS Nano. 2011 Mar 22;5(3):1617-22. doi: 10.1021/nn100855n. Epub 2011 Feb 22.
We fabricate, pattern, and analyze thin films composed of multilayer graphene nanoribbons. These films are conductive at room temperature but depict noticeable insulating behavior at low temperatures (<20 K) due to their disordered structure. We study the transport in this strong localization regime by analyzing the dependence of resistivity on temperature and electric and magnetic fields in the framework of the variable range hopping theory. Resistivity dependence on the magnetic field confirms the insulating behavior of the films and can be fitted effectively by forward interference scattering and wave function shrinkage models at low and high magnetic field regimes, respectively. We extract large localization lengths in the range of ∼45-90 nm from both the magnetic and electric field dependence of resistivity and relate these values to the high conductance in the nanoribbons and/or good contact between them. By revealing the fundamental structural and transport properties of graphitic nanoribbon films, our results help devise methods to further improve these films for electronic and photonic device applications.
我们制造、图案化和分析了由多层石墨烯纳米带组成的薄膜。这些薄膜在室温下是导电的，但由于其无序结构，在低温（<20 K）下表现出明显的绝缘行为。我们通过在变程跳跃理论的框架内分析电阻对温度和电场、磁场的依赖关系来研究这个强局域化区域的输运。电阻对磁场的依赖性证实了薄膜的绝缘行为，并且可以通过前向干涉散射和波函数收缩模型在低磁场和高磁场区域分别有效地拟合。我们从电阻对磁场和电场的依赖性中提取出了大约 45-90nm 的大局域长度，并将这些值与纳米带中的高电导和/或它们之间的良好接触联系起来。通过揭示石墨纳米带薄膜的基本结构和输运性质，我们的结果有助于设计进一步改进这些薄膜的方法，以用于电子和光子器件应用。
