Department of Chemistry, Rice University, 6100 Main Street, Houston, Texas 77005, United States.
ACS Nano. 2011 Oct 25;5(10):8187-92. doi: 10.1021/nn202829y. Epub 2011 Sep 12.
Here we demonstrate a general transfer-free method to directly grow large areas of uniform bilayer graphene on insulating substrates (SiO(2), h-BN, Si(3)N(4), and Al(2)O(3)) from solid carbon sources such as films of poly(2-phenylpropyl)methysiloxane, poly(methyl methacrylate), polystyrene, and poly(acrylonitrile-co-butadiene-co-styrene), the latter leading to N-doped bilayer graphene due to its inherent nitrogen content. Alternatively, the carbon feeds can be prepared from a self-assembled monolayer of butyltriethoxysilane atop a SiO(2) layer. The carbon feedstocks were deposited on the insulating substrates and then caped with a layer of nickel. At 1000 °C, under low pressure and a reducing atmosphere, the carbon source was transformed into a bilayer graphene film on the insulating substrates. The Ni layer was removed by dissolution, affording the bilayer graphene directly on the insulator with no traces of polymer left from a transfer step. The bilayer nature of as-grown samples was demonstrated by I(G)/I(2D) Raman mapping, the statistics of the full-width at half-maximum of the Raman 2D peak, the selected area electron diffraction patterns over a large area, and randomly imaged graphene edges by high-resolution transmission electron microscopy.
在这里，我们展示了一种通用的无转移方法，可直接从固体碳源（如聚（2-苯基丙基）甲基硅氧烷、聚甲基丙烯酸甲酯、聚苯乙烯和丙烯腈-丁二烯-苯乙烯共聚物）在绝缘衬底（SiO2、h-BN、Si3N4 和 Al2O3）上生长大面积均匀的双层石墨烯，这导致由于其固有的氮含量，双层石墨烯掺杂氮。或者，碳进料可以由二氧化硅层上的丁基三乙氧基硅烷自组装单层制备。碳原料沉积在绝缘衬底上，然后用一层镍覆盖。在 1000°C 下，在低压和还原气氛下，碳源在绝缘衬底上转化为双层石墨烯膜。通过溶解去除 Ni 层，直接在绝缘体上获得双层石墨烯，没有转移步骤留下的聚合物痕迹。通过 I(G)/I(2D)拉曼映射、拉曼 2D 峰半高全宽的统计、大面积选区电子衍射图案以及高分辨率透射电子显微镜随机成像的石墨烯边缘，证明了生长样品的双层性质。
