Parameter Space of Atomic Layer Deposition of Ultrathin Oxides on Graphene.
ACS applied materials & interfaces
American Chemical Society
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Aria, I., Nakanishi, K., Xiao, L., Braeuninger-Weimer, P., Sagade, A., Alexander-Webber, J. A., & Hofmann, S. (2016). Parameter Space of Atomic Layer Deposition of Ultrathin Oxides on Graphene.. ACS applied materials & interfaces, 8 30564-30575. https://doi.org/10.17863/CAM.6819
Atomic layer deposition (ALD) of ultrathin aluminum oxide (AlO$_x$) films was systematically studied on supported chemical vapor deposition (CVD) graphene. We show that by extending the precursor residence time, using either a multiple-pulse sequence or a soaking period, ultrathin continuous AlO$_x$ films can be achieved directly on graphene using standard H$_2$O and trimethylaluminum (TMA) precursors even at a high deposition temperature of 200 °C, without the use of surfactants or other additional graphene surface modifications. To obtain conformal nucleation, a precursor residence time of >2s is needed, which is not prohibitively long but sufficient to account for the slow adsorption kinetics of the graphene surface. In contrast, a shorter residence time results in heterogeneous nucleation that is preferential to defect/selective sites on the graphene. These findings demonstrate that careful control of the ALD parameter space is imperative in governing the nucleation behavior of AlO$_x$ on CVD graphene. We consider our results to have model system character for rational two-dimensional (2D)/non-2D material process integration, relevant also to the interfacing and device integration of the many other emerging 2D materials.
We acknowledge funding from the EPSRC (Grant EP/ K016636/1, GRAPHTED) and ERC (Grant 279342, InsituNANO). J.A.A.-W. acknowledges a Research Fellowship from Churchill College, Cambridge, U.K.
European Research Council (279342)
This record's DOI: https://doi.org/10.17863/CAM.6819
This record's URL: https://www.repository.cam.ac.uk/handle/1810/261610