Grzeszczyk M, Molas M R, Nogajewski K, Bartoš M, Bogucki A, Faugeras C, Kossacki P, Babiński A, Potemski M
Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093, Warsaw, Poland.
Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, 38042, Grenoble, France.
Sci Rep. 2020 Mar 18;10(1):4981. doi: 10.1038/s41598-020-61673-0.
Atomically thin materials, like semiconducting transition metal dichalcogenides (S-TMDs), are highly sensitive to the environment. This opens up an opportunity to externally control their properties by changing their surroundings. Photoluminescence and reflectance contrast techniques are employed to investigate the effect of metallic substrates on optical properties of MoSe monolayer (ML). The optical spectra of MoSe MLs deposited on Pt, Au, Mo and Zr have distinctive metal-related lineshapes. In particular, a substantial variation in the intensity ratio and the energy separation between a negative trion and a neutral exciton is observed. It is shown that using metals as substrates affects the doping of S-TMD MLs. The explanation of the effect involves the Schottky barrier formation at the interface between the MoSe ML and the metallic substrates. The alignment of energy levels at the metal/semiconductor junction allows for the transfer of charge carriers between them. We argue that a proper selection of metallic substrates can be a way to inject appropriate types of carriers into the respective bands of S-TMDs.
原子级薄材料，如半导体过渡金属二硫属化物（S-TMDs），对环境高度敏感。这为通过改变其周围环境来外部控制其性质提供了一个机会。采用光致发光和反射率对比技术来研究金属衬底对MoSe单分子层（ML）光学性质的影响。沉积在Pt、Au、Mo和Zr上的MoSe ML的光谱具有独特的与金属相关的线形。特别是，观察到负三激子和中性激子之间的强度比和能量间距有显著变化。结果表明，使用金属作为衬底会影响S-TMD ML的掺杂。对这种效应的解释涉及到在MoSe ML与金属衬底之间的界面处形成肖特基势垒。金属/半导体结处的能级对齐允许电荷载流子在它们之间转移。我们认为，适当选择金属衬底可以作为一种将适当类型的载流子注入到S-TMDs各自能带中的方法。
