Atomic layer deposited aluminum oxide films on graphite and graphene studied by XPS and AFM

Epitaxial graphene (EG) grown by solid‐state decomposition of SiC is a promising material for future graphenebased electronics. On EG, the fabrication of a field‐effect device requires the deposition of suitable gate insulator. Atomic layer deposition (ALD) of aluminum oxide might be useful for this purpose. Therefore, we investigated the growth of ALD‐Al 2 O 3 on highly oriented pyrolytic graphite (HOPG) and EG by atomic force microscopy (AFM), photoelectron spectroscopy (XPS) and Raman spectroscopy. Water as oxidant in the ALD process leads to inhomogeneous nucleation, whereas ozone leads to the formation of closed oxide layers. However, significant degradation of the EG takes place at higher temperatures and ozone exposure as witnessed by XPS and Raman spectroscopy. Careful adjustment of the process parameters allows reducing the damage to a level undetectable in XPS while providing enough nucleation centers for the formation of a closed Al 2 O 3 film potentially suitable as a gate insulator (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)