title: Hydrophobic Surface Treatment and Interrupted Atomic Layer Deposition for Highly Resistive Al2O3Films on Graphene.
abstract: The deposition of thin and uniform dielectric film on graphene is an important step for electronic applications. Here, we tackled this problem by combining a simple chemical treatment of graphene surface and a modification of standard atomic layer deposition (ALD). Instead of common approaches trying to convert hydrophobic graphene surface into hydrophilic one, we took the opposite way by applying a self-assembled-monolayer, hexamethyldisilazane (HMDS) to make defect-independent, more hydrophobic surface condition. In addition, Al2O3ALD using trimethylaluminum (TMA) and water (H2O) was interrupted several times and the surface was air-exposed during the interruption to seed the following ALD processes. This combination greatly improved the uniformity of dielectric film and accomplished a successful deposition of 10 nm-thick Al2O3on graphene with subnanometer roughness except for the locations of wrinkles and poly(methyl methacrylate) (PMMA) residues. Electrochemical impedance measurements revealed a 300-fold increase in the charge-transfer resistance by employing this modified ALD process. No change in the Raman spectra was observed after the dielectric film growth, demonstrating that the method proposed here is nondetrimental to the graphene quality.
authors.affiliation: Department of Physics and Graphene Research Institute, Sejong University , Seoul 05006, Korea.
authors.forename: Jae Ho
authors.initials: JH
authors.lastname: Jeon
authors.affiliation: Department of Physics and Graphene Research Institute, Sejong University , Seoul 05006, Korea.
authors.forename: Sahng-Kyoon
authors.initials: SK
authors.lastname: Jerng
authors.affiliation: Department of Physics and Graphene Research Institute, Sejong University , Seoul 05006, Korea.
authors.forename: Kamran
authors.initials: K
authors.lastname: Akbar
authors.affiliation: Department of Physics and Graphene Research Institute, Sejong University , Seoul 05006, Korea.
authors.forename: Seung-Hyun
authors.initials: SH
authors.lastname: Chun
keywords: Al2O3; atomic layer deposition; chemical vapor deposition; graphene; hexamethyldisilazane