Berlin 2024 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 36: Poster III
HL 36.13: Poster
Wednesday, March 20, 2024, 18:00–20:30, Poster E
Gas sensing of WSi2N4 in dark and bright environments — •Mustapha Driouech, Muhammad Sufyan Ramzan, and Caterina Cocchi — Carl von Ossietzky Universität Oldenburg
Two-dimensional materials are highly promising for gas sensing. In this work, we investigate the adsorption of the three common environmental gas molecules, namely O2, CO2, and H2O on monolayer WSi2N4. Using density functional theory, we simulate molecular adsorption and evaluate resulting changes in the electronic structure of the monolayer in the dark and bright environment. The latter (former) is mimicked by promoting (removing) an electron to the conduction (valance) state. Our results show that all gas molecules are physically adsorbed on the WSi2N4 surface with small charge transfer in the dark. The presence of photogenerated electrons and holes changes the strength of gas adsorption. While with CO2 and H2O WSi2N4 behaves similarly in the dark and light environment, bright conditions enhance the interaction of WSi2N4 with O2. As a result, charge transfer is increased compared to the dark, and substrate oxidation is promoted. Moreover, in terms of electronic properties, O2 molecules contribute to the valence band maximum of the system regardless of the environment, making WSi2N4 a promising material for oxygen sensing.
Keywords: Gas Sensors; 2D Materials; photogenerated charge carriers