AI 中文总结
本研究提出石墨栅极架构隔离双层石墨烯天然边缘，实现静电定义霍尔棒，揭示边界散射特征，制备的场效应晶体管获创纪录量子迁移率。
AI 中文摘要
我们为双层石墨烯器件引入了一种石墨栅极架构，该架构可使有源器件与天然石墨烯边缘完全隔离。利用单一图案化石墨栅极层，我们实现了完全由静电定义的霍尔棒。纵向和霍尔测量揭示了介观输运特征，包括与边界散射相关的霍尔效应淬灭和磁阻峰。这些介观特征对载流子密度的依赖表明，有效沟道宽度随费米能级和栅极定义边界处的静电限制而增加，且说明载流子在静电边界处发生散射。拉曼光谱和开尔文探针力显微镜表明，该边界因所用制备方法而存在无序。相比之下，采用相同架构制备的场效应晶体管中的量子迁移率不受边界散射限制，且量子振荡在低至4 mT时仍可见，这表明其量子迁移率达到了创纪录的2.5×10^6 cm²/Vs。
英文摘要
We introduce a graphite-gated architecture for bilayer graphene devices in which the active device is completely isolated from the natural graphene edges. Using a single patterned graphite-gate layer, we realize a fully electrostatically defined Hall-bar. Longitudinal and Hall measurements reveal mesoscopic transport features, including Hall-effect quenching and magnetoresistance peaks associated with boundary scattering. The dependence of the mesoscopic features on the carrierdensity shows that the effective channel width increases with the Fermi level and the electrostatic confinement at the gate-defined boundaries, and indicates that the carriers scatter at the electrostatic boundary. Raman spectroscopy and Kelvin probe force microscopy suggest that this boundary is disordered due to the used fabrication methods. Comparably, the quantum mobility in a fieldeffect transistor fabricated with the same architecture is not limited by boundary scattering and the visibility of quantum oscillations down to 4 mT suggests a record value of 2.5 x 10^6 cm2/Vs.
