Visualization of domain and interfacial structures of Monolayer semiconductors by Nonlinear Optical Microscopy*

Domain and interfacial structures of the monolayer transition metal dichalcogenides (TMD) are significant to diverse physics and performances. Unique carrier transportation and bandgap tunability could be engineered with inter-grain twisting, which provide an extra degree of freedom for device designing. Here, the correlation between GBs and inter-grain twisting in monolayer WS₂ is studied using nonlinear microscopy. With the change of inter-grain twisting, domain and interfacial structures of the monolayer is monitored and studied.