Dresden 2014 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 99: Graphene: Spintronics, Transistors, and Sensors (organized by HL)
TT 99.2: Talk
Thursday, April 3, 2014, 15:15–15:30, POT 081
Atomic layer deposited aluminum oxide on epitaxial graphene without surface activation — •Peter Wehrfritz1, Florian Speck2, Felix Fromm1, Stefan Malzer3, and Thomas Seyller1 — 1TU Chemnitz, Institut für Physik, Chemnitz, Deutschland — 2FAU Erlangen-Nürnberg, Department Physik, Erlangen, Deutschland — 3FAU Erlangen-Nürnberg, Angewandte Physik, Erlangen, Deutschland
Graphene with its high charge carrier mobility is a promising material for analog RF field effect transistors. The preparation of the required insulating layer is still challenging. Atomic layer deposition (ALD) has been extensively studied in the context of alternative dielectrics for silicon-based field effect transistors owing to its capabilities to produce high-quality, homogeneous oxide layers. However, nucleation of ALD growth is strongly suppressed on inert graphene surfaces.
In this contribution we present an approach to obtain conformal aluminum oxide (Al2O3) on epitaxial monolayer graphene on silicon carbide (SiC). We demonstrate that closed layers of Al2O3 can be deposited on the so called buffer layer. This buffer layer covered by ALD-Al2O3 can then be decoupled from the SiC substrate by means of hydrogen intercalation yielding quasi-freestanding monolayer graphene with an insulating dielectric on top. We investigated the quality of the graphene layer and ALD-Al2O3 using X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, AFM, and Hall effect measurements.