Impact of Thermal Annealing on the Interaction of Monolayer MoS₂ on Au

We have investigated the impact of thermal annealing on the interaction of single layer MoS₂and Au using Raman Spectroscopy. Au-assisted exfoliation results in single layer MoS₂ which has weakly- and strongly-coupled regions where the strongly-coupled regions are n-doped and relatively unstrained while the weakly-coupled regions are p-doped and tensile strained. The observed nanoscale inhomogeneities may result in Au contacts having a large variability in performance. Our data also show that monolayer MoS₂ starts to decouple from Au at above 100 °C, becoming fully decoupled above 200-250 °C. This indicates that monolayer MoS₂ produced by Au-assisted exfoliation may be more easily transferred off Au at high temperatures. Our results also show that the overall areal coverage of strongly-coupled regions does not increase by thermal annealing while the degree of hybridization becomes more inhomogeneous at annealing temperatures above 100 °C.