Dresden 2017 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 40: Focus Session: Charge Transport at Surfaces and Nanostructures with Multi-probe Techniques II

O 40.3: Vortrag

Dienstag, 21. März 2017, 14:45–15:00, WIL C307

Kelvin probe force microscopy as a tool to measure local transport properties in graphene on SiO2 — Philip Willke¹, •Anna Sinterhauf¹, Christian Möhle¹, Thomas Kotzott¹, Hak Ki Yu^{2, 3, 4}, Alec Wodtke^2,3, and Martin Wenderoth¹ — ¹IV. Physical Institute, University of Göttingen, 37077, Göttingen, Germany — ²Institute for Physical Chemistry, University of Göttingen, 37077, Göttingen, Germany — ³Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany — ⁴Department of Materials Science & Engineering, Ajou University, Suwon, 443-749, South Korea

We combine the AFM-based method of Kelvin probe force microscopy (KPFM) with an additionally applied electric field across the sample to map the electrostatic potential on a nanometer scale. Thus we investigate the local voltage drop in graphene on SiO2 under ambient conditions and room temperature [1]. We can quantify the variation of the local sheet resistance and resolve a localized voltage drop at folded wrinkles for the first time. Furthermore, we map local resistances as a function of temperature by using Joule heating. These measurements show that the local monolayer sheet resistance reflects the macroscopic increase in resistance with temperature while the defect resistance for folded wrinkles is best described by a temperature-independent model which we attribute to interlayer tunneling. This work was supported by SPP 1459 'Graphene'.

[1] Willke et al., Carbon 102, 470-476 (2016)