Three-dimensionally stacked Al^sub 2^O^sub 3^/graphene oxide for gas barrier applications

We investigated the growth behavior of Al2O3 using atomic layer deposition (ALD) on the surface of chemical vapor deposition (CVD)-grown graphene and graphene oxide (GO). While selective ALD growth was observed on CVD-grown graphene along defective sites, smooth and continuous films were grown on GO without selective growth. Linear growth of Al2O3 on GO was observed without a nucleation region or growth selectivity. This result indicates that the ALD film growth is more suitable for GO because of the abundant and homogeneously distributed reactive sites over its basal plane. By taking advantage of GO as an ideal substrate for the ALD growth of metal oxides, highly aligned, multiple-stacked, three-dimensional Al2O3/GO structures were fabricated, which showed much better effective gas barrier characteristics (1.73 × 10-4 g/m2day) than that exhibited by pristine single Al2O3 thin films of the same thickness.