Sunday, October 11, 2015

Wafer-scale single-domain-like graphene by defect-selective ALD of hexagonal ZnO

Korean researchers report defect-selective atomic layer deposition (ALD) for stitching grain boundaries of CVD graphene with ZnO 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.

Wafer-scale single-domain-like graphene by defect-selective atomic layer deposition of hexagonal ZnO

Kyung Sun Park, Sejoon Kim, Hongbum Kim, Deokhyeon Kwon, Yong-Eun Koo Lee, Sung-Wook Min, Seongil Im, Hyoung Joon Choi, Seulky Lim, Hyunjung Shin, Sang Man Koo and Myung Mo Sung

Nanoscale, 2015, Advance Article, DOI: 10.1039/C5NR05392GAccepted 24 Sep 2015



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.