Regensburg 2013 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 24: Transport & Diffusion II
MM 24.4: Talk
Tuesday, March 12, 2013, 12:30–12:45, H26
Contact resistance and field effects of graphene field effect transistors probed by Kelvin Probe Force Microscopy — •Carlos Alvarado1, Gerd Bacher1, Wolfgang Mertin1, and Daniel Neumaier2 — 1Werkstoffe der Elektrotechnik and CENIDE, Universität Duisburg-Essen, 47057 Duisburg, Germany — 2AMO GmbH, 52074 Aachen, Germany
A promising route for large area, high quality graphene sheets suitable for electronic applications is the CVD growth through cooper foils. On its way to become the new material of choice in high frequency electronics, transistors based on CVD grown graphene have to be fabricated and their electrical properties have to be understood on a microscopic scale.
Here, back gate field effects transistors based on CVD grown graphene have been prepared. By spatially resolved Kelvin Probe Force Microscopy (KPFM) on an operating device, the voltage drop profile at the contacts and the potential distribution along the graphene channel are directly measured. Our results show how defects like contaminations or vacancies alter the voltage drop profile and the contact resistance, which is confirmed by 4-probe measurements. We are able to visualize the changes in the potential distribution due to back-gated field effects by KPFM imaging, which opens the possibility to relate the macroscopic I-V characteristics with the distribution of the electrical potential in the device on the nanoscale