Berlin 2012 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 102: Transport: Graphene 2 (jointly with TT, MA, DY, DS, O)

HL 102.7: Vortrag

Freitag, 30. März 2012, 11:15–11:30, BH 334

Monolithic Epitaxial Graphene Electronics — •Stefan Hertel¹, Daniel Waldmann¹, Johannes Jobst¹, Sergey Reshanov², Adolf Schöner², Michael Krieger¹, and Heiko B. Weber¹ — ¹Chair of Applied Physics, Erlangen, Germany — ²ACREO AB, Kista, Sweden

We developed a scheme to fabricate transistors with high switching performance by employing the whole system epitaxial graphene consisting of the graphene itself, but also include the semiconducting silicon carbide substrate and their common interface.

We used n-type SiC as conducting channel and tailored two different interfaces to the graphene: (a) monolayer epitaxial graphene [1] to provide ohmic contacts and (b) quasi-freestanding bilayer graphene [2](as achieved by hydrogen intercalation of MLG) to get Schottky-like contacts. We developed a method to produce both species side-by-side on the same chip. The resulting transistor works similar to a MeSFET with graphene as source and drain material but also as gate metal. In principal one single lithography step is sufficient to fabricate a transistor.

We demonstrate an epitaxial graphene transistor with on/off ratios exceeding 4 orders of magnitude at room temperature which can operate in both normally-on and normally-off operation mode, adjustable using a parametric backgate voltage. No damping was observed up to MHz frequencies.

[1] Emtsev et al., Nature Material 8, 203-207 (2009).
Speck et al., Applied Physics Letters 99, 122106 (2011).