Boron nitride substrates for high-quality graphene electronics
Boron nitride substrates for high-quality graphene electronics
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DOI：
10.1038/nnano.2010.172
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发表时间：
2010-10-01
影响因子：
38.3
通讯作者：
Hone, J.
中科院分区：
文献类型：
--
作者：
Dean, C. R.;Young, A. F.;Hone, J.
标准SiO2衬底上的石墨烯器件是高度无序的，表现出远不如石墨烯的预期固有性质的特性（1-12）。尽管将石墨烯悬浮在衬底上方导致器件质量的显著改善（13，14），但这种几何形状对器件架构和功能施加了严重限制。因此，越来越需要确定允许衬底支撑的几何形状同时保持悬浮样品所实现的质量的样品。六方氮化硼（h-BN）是一种有吸引力的衬底，因为它具有原子级光滑的表面，相对没有悬挂键和电荷陷阱。它还具有类似于石墨的晶格常数，并且具有大的光学声子模式和大的电带隙。在这里，我们报告的制造和表征的高品质剥离的单层和双层石墨烯器件的单晶h-BN基板上，通过使用机械转移过程。h-BN衬底上的石墨烯器件具有比SiO2上的器件好几乎一个数量级的迁移率和载流子不均匀性。这些器件还显示出降低的粗糙度、本征掺杂和化学反应性。以受控方式组装结晶层状材料的能力允许在其他有前景的衬底上制造石墨烯器件（15），并允许实现更复杂的石墨烯异质结构。
Graphene devices on standard SiO2 substrates are highly disordered, exhibiting characteristics that are far inferior to the expected intrinsic properties of graphene(1-12). Although suspending the graphene above the substrate leads to a substantial improvement in device quality(13,14), this geometry imposes severe limitations on device architecture and functionality. There is a growing need, therefore, to identify dielectrics that allow a substrate-supported geometry while retaining the quality achieved with a suspended sample. Hexagonal boron nitride (h-BN) is an appealing substrate, because it has an atomically smooth surface that is relatively free of dangling bonds and charge traps. It also has a lattice constant similar to that of graphite, and has large optical phonon modes and a large electrical bandgap. Here we report the fabrication and characterization of high-quality exfoliated mono- and bilayer graphene devices on single-crystal h-BN substrates, by using a mechanical transfer process. Graphene devices on h-BN substrates have mobilities and carrier inhomogeneities that are almost an order of magnitude better than devices on SiO2. These devices also show reduced roughness, intrinsic doping and chemical reactivity. The ability to assemble crystalline layered materials in a controlled way permits the fabrication of graphene devices on other promising dielectrics(15) and allows for the realization of more complex graphene heterostructures.