Berlin 2015 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 39: Posters II (Topological insulators; Graphene; Spintronics and spin physics; Quantum information science)

HL 39.15: Poster

Dienstag, 17. März 2015, 14:00–20:00, Poster F

Correlation between structural and electrical properties of transition metal dichalcogenide transistors — •Florian Winkler¹, Sven Borghardt², Martial Duchamp¹, Rafal E. Dunin-Borkowski¹, and Beata E. Kardynal² — ¹Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute 5, Research Centre Jülich, Germany — ²Peter Grünberg Institute 9, Research Centre Jülich, Germany

Layered transition metal dichalcogenides (TMDs) have been researched intensively as materials for low power transistors. Strong spin orbit interactions combined with a direct bandgap in monolayers of MX₂ (M: Mo, W; X: S, Se) make them very attractive for spintronics and valleytronics. The realization of the promise offered by these materials depends on the ability to access their intrinsic properties, rather than measuring the effect of the environment.

In this work, we compare the electrical conductance of TMD field effect transistors with the structural properties of TMD films that were prepared in the same way. We study several combinations of channel materials (WSe₂ and MoS₂) and metals (Sc, Ti/Au, Pd) prepared using different techniques and measured under different conditions. We show clear correlations between the level of contamination of the films and their measured electrical characteristics. We discuss the effect of metal deposition on the compositions and properties of the TMD films. The results strongly suggest that the performance of TMD transistors is limited by the contamination of the channel material, as well as by interactions of metals with the TMD during metal deposition.