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 ${\mathrm{Al}}_2{\mathrm{O}}_3$ layers. While the trimethylaluminum $\left(\mathrm{TMA}\right)∕{\mathrm{H}}_2\mathrm{O}$ process caused selective deposition only along step edges, the $\mathrm{TMA}∕{\mathrm{O}}_3$ process began to provide nucleation sites on the basal planes of the surface. ${\mathrm{O}}_3$ pretreatment, immediately followed by the ALD process with $\mathrm{TMA}∕{\mathrm{O}}_3$ chemistry, formed ${\mathrm{Al}}_2{\mathrm{O}}_3$ 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.