Investigation On The Preparation And Properties Of Monolayer Molybdenum Disulfide

Monolayer molybdenum disulphide?MoS₂?with excellent optical and electrical properties has been extensively studied.However,before the successful preparation of monolayer MoS₂ based nano-device,the reproducible growth method of monolayer MoS₂ with large area and good qualities should be developed.Lots of methods have been used in the growth of monolayer MoS₂.Here we studied the growth behavor of large-scale monolayer MoS₂ through chemical vapor deposition?CVD?method with MoS₂ powders as precursor.In this work,we adjust the CVD method of ventilation control,making the MoS₂ growth in atmospheric conditions,and synthesized large-scale monolayer MoS₂ successfully.The effects of different temperature as well as the time of nucleation and growth during synthesizing monolayer MoS₂ were studied systematically.It is found that the longer nucleation time will inhibit the growth of MoS₂,and the longer the growth time is,the thicker the film will be.After the investigated of synthesizing monolayer MoS₂ on different substrates,like h-BN and graphene,is found that the residual polymethyl methacrylate?PMMA?on the substrates surface during the transfer discourage the growth of monolayer MoS_2.Further study of synthesis on SiO₂/Si with manganese?Mn?deposited shows that the addition of Mn not only reduces the experimental temperature requirements,but also promote the heterogeneous nucleation of MoS₂,which makes the as-deposited monolayer MoS₂ exhibit unique luminescence properties.We also introduce the CVD method to synthesize amorphous MoS₂.The hydrogen evolution reaction?HER?of amorphous MoS₂ was investigated.The amorphous MoS₂ showed excellent catalytic activity and photoresponse,and the properties of the film is similar to P-type semiconductor.