Dresden 2017 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 56: Poster Session: Low-Dimensional Systems
TT 56.1: Poster
Mittwoch, 22. März 2017, 15:00–19:00, P2-OG4
Oxidation and temperature dependent resistivity of VSe2 flakes — •Benedikt Brechtken, Christopher Belke, Hennrik Schmidt, and Rolf J. Haug — Institut für Festkörperphysik, Leibniz Universität Hannover, 30167 Hannover
Many 2D materials are of interest for the design of innovative devices. But some of them are chemically less stable than the well known graphene. The influence on the properties of VSe2 flakes through oxidation in ambient air at room temperature is studied. Therefore VSe2 flakes were fabricated with the scotch tape method under nitrogen atmosphere and Cr/Au-contacts were build on the flakes with e-beam lithography.
The surface oxidation was investigated via optical microscopy and atomic force microscopy. A slow oxidation and formation of small oxidhills on the flake surface could be observed. A two point measurement at room temperatur showed a resistance of 250 Ohm for a 30 nm thick flake.
Furthermore the temperature dependence of the resistivity was studied in a He cryostat. Between room temperature and the Debye temperature a linear dependance was measured. Under the Debye temperature the dependance showed a power-law relation. That is a classical metallic behavior as it was found in VSe2 bulk material [1]. Around 95 K a charge-density-wave was expected [2]. That could not be measured, most likely because of the low mobility of the sample.
[1] A. Toriumi, and S. Tanaka, Physika 105B, 141, (1981)
[2] J. Yang, et al., Applied Physics Letters 105,063109 (2014)