Impact of thermal annealing on the interaction between monolayer MoS2 and Au

We have investigated the impact of thermal annealing on the interaction of single layer 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 {\deg}C. Our data also show that monolayer MoS2 starts to decouple from Au around 100 {\deg}C, becoming fully decoupled above 250 {\deg}C, suggesting that monolayer MoS2 produced by Au-assisted mechanical exfoliation may be more easily transferred off Au at elevated temperatures.