Substrate induced anomalous electrostatic and photoluminescence propeties of monolayer MoS2 edges

Monolayer MoS 2 is an emerging two-dimensional semiconductor with wide-ranging potential applications in the next generation electronic and optoelectronic devices. Understanding the influences of the supporting substrates on the physical properties of grown MoS 2 is an important step toward its applications. Here we synthesized two typical rhomboid shaped MoS 2 on MoO 2 and triangle shaped MoS 2 on SiO 2 /Si substrates and characterized them by multiple means of X-Ray Photoemission Spectroscopy, Atomic Force Microscopy , Electrostatic Force Microscopy, Raman and Photoluminescence techniques. We found that triangle shaped MoS 2 exhibits different core level spectra compared with rhomboid shaped MoS 2 , attributed to dissimilar charge transfer with the underlying SiO 2 substrate. Interestingly, the triangle shaped MoS 2 single crystals exhibit distinct electrostatic and photoluminescence properties at center and edges. The underlying mechanism is proposed that partial decoupling of MoS 2 at edges from SiO 2 substrate induces different doping level and strain effects, resulting in anomalous physical properties at edges. The results reported here demonstrate that doping and strain effects induced by substrates have a significant influence on physical properties of monolayer triangle shaped MoS 2 ，which can be generally applicable to other transition metal dichalcogenides materials.