Band-bending induced by charged defects and edges of atomically thin transition metal dichalcogenide films

Abstract : We report scanning tunneling microscopy/spectroscopy (STM/STS) investigations of the bandbending in the vicinity of charged point defects and edges of monolayer MoSe$_2$ and mono- and trilayer WSe$_2$ films deposited on graphitized silicon carbide substrates. By tracing the spatial evolution of the structures of the STS spectra, we evaluate the magnitude and the extent of the band-bending to be equal to few hundreds milielectronvolts and several nanometres, respectively. With the aid of a simple electrostatic model, we show that the spatial variation of the Coulomb potential close to the film edges can be well reproduced by taking into account the metallic screening by graphene. Additionally, the analysis of our data for trilayer WSe$_2$ provides reasonable estimations of its dielectric constant ($\epsilon_{WSe}$$_2$ = 20) and of the magnitude of the charge trapped at the defect site (Q = $+e$).
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Contributor : Toai Le Quang <>
Submitted on : Tuesday, June 12, 2018 - 4:18:37 PM
Last modification on : Friday, April 12, 2019 - 4:23:12 PM

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T. Le Quang, K. Nogajewski, M. Potemski, Minh Tuan Dau, M. Jamet, et al.. Band-bending induced by charged defects and edges of atomically thin transition metal dichalcogenide films. 2D Materials, IOP Publishing, 2018, 5, pp.035034. ⟨10.1088/2053-1583/aac65a⟩. ⟨hal-01813835⟩

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