NaCl-Assisted CVD Synthesis, Transfer and Persistent Photoconductivity Properties of Two-Dimensional Transition Metal Dichalcogenides

Transition metal dichalcogenides (TMDC), such as MoS 2 , WS 2 have attracted attention due to their mechanical and electronic properties in their two dimensional (2D) structures. Here, we report a facile growth of monolayer TMDC using oxide source materials with the assistant of NaCl. The addition of NaCl can enhance the lateral growth and widen the growth window of TMDC. Through carefully controlling the growth parameters, large area growth of TMDC can be achieved. Two steps E-beam lithography was utilized to fabricate electrodes of TMDC. The phototransistors made from the CVD grown TMDC show strong persistent photoconductivity (PPC). It was finally shown that TMDC device capping with h-BN could have suppressed PPC effects.