Band Alignment at Au/MoS2 Contacts: Thickness Dependence of Exfoliated Flakes
- 등재 SCIE, SCOPUS
- 발행기관 American Chemical Society
- 발행년도 2017
- URI http://www.dcollection.net/handler/ewha/000000149871
- 본문언어 영어
- Published As http://dx.doi.org/10.1021/acs.jpcc.7b07511
초록/요약
We investigated the surface potential (Vsurf) of exfoliated MoS2 flakes on bare and Au-coated SiO2/Si substrates using Kelvin probe force microscopy. The Vsurf of MoS2 single layers was larger on the Au-coated substrates than on the bare substrates; our theoretical calculations indicate that this may be caused by the formation of a larger electric dipole at the MoS2/Au interface leading to a modified band alignment. Vsurf decreased as the thickness of the flakes increased until reaching the bulk value at a thickness of a20 nm (a30 layers) on the bare and a80 nm (a120 layers) on the Au-coated substrates, respectively. This thickness dependence of Vsurf was attributed to electrostatic screening in the MoS2 layers. Thus, a difference in the thickness at which the bulk Vsurf appeared suggests that the underlying substrate has an effect on the electric-field screening length of the MoS2 flakes. This work provides important insights to help understand and control the electrical properties of metal/MoS2 contacts. © 2017 American Chemical Society.
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