Structural, optical and electrostatic properties of single and fewlayers MoS2 : effect of substrate

Robinson, Benjamin and Giusca, Cristina and Gonzalez, Yurema and Kay, Nicholas and Kazakova, Olga and Kolosov, Oleg (2015) Structural, optical and electrostatic properties of single and fewlayers MoS2 : effect of substrate. 2D Materials, 2 (1): 015005. ISSN 2053-1583

PDF (2015 Structural, optical and electrostatic properties of single and few-layers MoS2_effect of substrate)
2015_Structural_optical_and_electrostatic_properties_of_single_and_few_layers_MoS2_effect_of_substrate.pdf - Published Version
Available under License Creative Commons Attribution.
Download (1MB)

Abstract

We have decoupled the intrinsic electrostatic effects arising in monolayer and few-layer MoS2 from those influenced by the flake-substrate interaction. Using ultrasonic force microscopy nanomechanical mapping, we identify the change from supported to suspended flake regions on a trenched substrate. These regions are correlated with the surface potential as measured by scanning Kelvin probe microscopy. Relative to the supported region, we observe an increase in surface potential contrast due to suppressed charge transfer for the suspended monolayer. Using Raman spectroscopy we observe a red shift of the E12g mode for monolayer MoS2 deposited on Si, consistent with a more strained MoS2 on the Si substrate compared to the Au substrate.