Abstract

We have investigated the impact of thermal annealing on the interaction between monolayer MoS₂ and Au using Raman spectroscopy. We found MoS₂ has two main modes of interactions with the underlying Au being either weakly-coupled or strongly-coupled. The regions strongly-coupled to Au are hybridized to Au, minimally strained, and electron-doped. The weakly-coupled regions are found to be slightly hole-doped with tensile strain of 1.0 %. The observed nanoscale inhomogeneities in doping would result in Au contacts having a large variability in performance. The overall areal coverage of the strongly-coupled regions is not increased by thermal annealing, and the variability in the degree of hybridization increases at annealing temperatures above 100 °C. Our data also show that monolayer MoS₂ starts to decouple from Au around 100 °C, becoming fully decoupled above 200–250 °C, suggesting that monolayer MoS₂ produced by Au-assisted mechanical exfoliation may be more easily transferred off Au at elevated temperatures.

Abstract

We have investigated the impact of thermal annealing on the interaction between monolayer MoS₂ and Au using Raman spectroscopy. We found MoS₂ has two main modes of interactions with the underlying Au being either weakly-coupled or strongly-coupled. The regions strongly-coupled to Au are hybridized to Au, minimally strained, and electron-doped. The weakly-coupled regions are found to be slightly hole-doped with tensile strain of 1.0 %. The observed nanoscale inhomogeneities in doping would result in Au contacts having a large variability in performance. The overall areal coverage of the strongly-coupled regions is not increased by thermal annealing, and the variability in the degree of hybridization increases at annealing temperatures above 100 °C. Our data also show that monolayer MoS₂ starts to decouple from Au around 100 °C, becoming fully decoupled above 200–250 °C, suggesting that monolayer MoS₂ produced by Au-assisted mechanical exfoliation may be more easily transferred off Au at elevated temperatures.

Abstract

We have investigated the impact of thermal annealing on the interaction between monolayer MoS₂ and Au using Raman spectroscopy. We found MoS₂ has two main modes of interactions with the underlying Au being either weakly-coupled or strongly-coupled. The regions strongly-coupled to Au are hybridized to Au, minimally strained, and electron-doped. The weakly-coupled regions are found to be slightly hole-doped with tensile strain of 1.0 %. The observed nanoscale inhomogeneities in doping would result in Au contacts having a large variability in performance. The overall areal coverage of the strongly-coupled regions is not increased by thermal annealing, and the variability in the degree of hybridization increases at annealing temperatures above 100 °C. Our data also show that monolayer MoS₂ starts to decouple from Au around 100 °C, becoming fully decoupled above 200–250 °C, suggesting that monolayer MoS₂ produced by Au-assisted mechanical exfoliation may be more easily transferred off Au at elevated temperatures.

Abstract

We have investigated the impact of thermal annealing on the interaction between monolayer MoS₂ and Au using Raman spectroscopy. We found MoS₂ has two main modes of interactions with the underlying Au being either weakly-coupled or strongly-coupled. The regions strongly-coupled to Au are hybridized to Au, minimally strained, and electron-doped. The weakly-coupled regions are found to be slightly hole-doped with tensile strain of 1.0 %. The observed nanoscale inhomogeneities in doping would result in Au contacts having a large variability in performance. The overall areal coverage of the strongly-coupled regions is not increased by thermal annealing, and the variability in the degree of hybridization increases at annealing temperatures above 100 °C. Our data also show that monolayer MoS₂ starts to decouple from Au around 100 °C, becoming fully decoupled above 200–250 °C, suggesting that monolayer MoS₂ produced by Au-assisted mechanical exfoliation may be more easily transferred off Au at elevated temperatures.