Conformal Al2O3 dielectric layer deposited by atomic layer deposition for graphene-based nanoelectronics

We present a facile route which combines the functionalization of a highly oriented pyrolytic graphite surface with an atomic layer deposition (ALD) process to allow for conformal Al2O3 layers. While the trimethylaluminum (TMA)∕H2O process caused selective deposition only along step edges, the TMA∕O3 process began to provide nucleation sites on the basal planes of the surface. O3 pretreatment, immediately followed by the ALD process with TMA∕O3 chemistry, formed Al2O3 layers without any preferential deposition at the step edges. This is attributed to functionalization of graphene by ozone treatment, imparting a hydrophilic character which is desirable for ALD deposition.