Department of Chemistry, Hanyang University, Seoul 133-791, Korea.
Department of Physics and Applied Physics, Yonsei University, Seoul 120-749, Korea.
Nanoscale. 2015 Nov 14;7(42):17702-9. doi: 10.1039/c5nr05392g.
Large-area graphene films produced by means of chemical vapor deposition (CVD) are polycrystalline and thus contain numerous grain boundaries that can greatly degrade their performance and produce inhomogeneous properties. A better grain boundary engineering in CVD graphene is essential to realize the full potential of graphene in large-scale applications. Here, we report a defect-selective atomic layer deposition (ALD) for stitching grain boundaries of CVD graphene with ZnO so as to increase the connectivity between grains. In the present ALD process, ZnO with a hexagonal wurtzite structure was selectively grown mainly on the defect-rich grain boundaries to produce ZnO-stitched CVD graphene with well-connected grains. For the CVD graphene film after ZnO stitching, the inter-grain mobility is notably improved with only a little change in the free carrier density. We also demonstrate how ZnO-stitched CVD graphene can be successfully integrated into wafer-scale arrays of top-gated field-effect transistors on 4-inch Si and polymer substrates, revealing remarkable device-to-device uniformity.
采用化学气相沉积（CVD）方法制备的大面积石墨烯薄膜为多晶薄膜，因此含有大量晶界，这会极大地降低其性能并产生不均匀的性质。在 CVD 石墨烯中进行更好的晶界工程对于实现石墨烯在大规模应用中的全部潜力至关重要。在这里，我们报告了一种缺陷选择性原子层沉积（ALD），用于缝合 CVD 石墨烯的晶界，以增加晶粒之间的连通性。在本ALD 过程中，主要在富含缺陷的晶界上选择性地生长具有六方纤锌矿结构的 ZnO，以产生具有良好连通晶粒的 ZnO 缝合 CVD 石墨烯。对于经过 ZnO 缝合的 CVD 石墨烯薄膜，在自由载流子密度仅有微小变化的情况下，晶粒间迁移率显著提高。我们还展示了如何成功地将 ZnO 缝合的 CVD 石墨烯集成到 4 英寸 Si 和聚合物衬底上的顶栅场效应晶体管晶圆级阵列中，显示出出色的器件间均匀性。
