Regensburg 2019 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 17: Two-dimensional Materials I (joint session HL/CPP)
HL 17.6: Vortrag
Dienstag, 2. April 2019, 10:45–11:00, H36
Effects of the Fermi Level Energy on the Adsorption of O2 to Monolayer MoS2 — •Philip Klement1, Christina Steinke3, Sangam Chatterjee1, Tim Wehling3, and Martin Eickhoff2 — 1Institute of Experimental Physics I and Center for Materials Research, Justus Liebig University Giessen, D-35392 Giessen, Germany — 2Institute of Solid State Physics, University of Bremen, D-28359 Bremen, Germany — 3Institute for Theoretical Physics and Bremen Center for Computational Material Sciences, University of Bremen, D-28359 Bremen, Germany
Two-dimensional transition metal dichalcogenides possess large surface-to-volume ratios that make them ideal candidates for sensing applications such as detecting the surface adsorption of specific gas molecules. The resulting changes of the electrical and optical properties allow for detection and analysis of interaction mechanisms at the sensing interface. Specifically, we investigate the influence of O2 adsorption on monolayer MoS2 and the role of the Fermi level energy in this process. We record the response in photoluminescence and transport properties of monolayer MoS2 upon O2 adsorption and the impact of external electric gating. We find an increase of the photoluminescence intensity and a reduction of the conductivity upon O2 adsorption, and show that the adsorption can be enhanced by an increase of the Fermi level energy. These results demonstrate that ionosorption of O2 on MoS2 by charge transfer only occurs if free carriers are available in the conduction band of MoS2. Furthermore, photoluminescence recording is rendered advantageous for sensing.