SKM 2021 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 3: Poster Session I
HL 3.19: Poster
Monday, September 27, 2021, 10:00–13:00, P
A field-effect-transistor based on the carbon allotropes diamond and graphene — •Vasilis Dergianlis, Martin Geller, Dennis Oing, Nicolas Wöhrl, and Axel Lorke — Faculty of Physics and CENIDE, University of Duisburg-Essen, Germany
Graphene is the two-dimensional carbon allotrope that exhibits exceptional mechanical strength and electron mobility. Due to its high conductivity, it is considered as one of the best conductors and can also be used as gate electrode in transistor-type devices. A second important carbon allotrope is diamond, which is a wide-bandgap semiconductor in its bulk form, where by hydrogen termination and exposure to ambient atmosphere, a two dimensional hole gas (2DHG) is formed on its surface.
In this work, we have combined the two aforementioned 2D carbon allotropes together with a thin layer of hexagonal Boron Nitride (h-BN) to a diamond-based FET. The sample consists of chemical vapor deposition-grown diamond, where a hydrogen termination induces a 2DHG on the surface as a conductive layer [1]. Graphene and hBN flakes were exfoliated and, using a dry-transfer method, placed onto the functionalized diamond surface. In this transistor-like structure, the h-BN serves as the gate-dielectric. As graphene is an ambipolar two-dimensional semiconductor itself, it can serve as both the gate electrode and tunable conductive channel. We show FET characterization of the graphene-gated structure with a mobility of 5 cm2/V · s and carrier density of p=3.7 · 1012 cm−2 at a gate voltage of Vg= −9 V [1] Oing, D., et al. Diamond and Related Materials 97, 107450 (2019).