Preparation And Photoelectric Properties Of Two-dimensional Transition Metal Selenide Laminated/Heterostructures

Two-dimensional transition metal dichalcogenides（TMDCs）are a unique class of layered materials with single/multi-atomic thickness and have wide-ranging potential for applications due to their excellent structural performance and tunable band gap.MoSe₂ and WSe₂,as new generation TMDC materials,have enormous research potential.However,the effective preparation of high-quality thin film materials with specific structures is an important factor limiting their widespread application.In addition,the different stacking structures between two-dimensional selenide layers are an important factor affecting their performance.Different growth of two-dimensional selenides results in various heterostructures,which have both the characteristics of tunable bandgap semiconductors and unique heterostructure interfaces that can exhibit a variety of unique properties.This provides a new avenue for the research and application of new high-performance optoelectronic devices.First of all,this paper uses chemical vapor deposition（CVD）to prepare MoSe₂and WSe₂ thin film materials.The controllable growth of high-quality MoSe₂ and WSe₂thin films is explored by changing various growth conditions such as growth sources,promoter salt types,reaction deposition temperature,and different substrates.Secondly,a series of characterization methods are used to study the various physical and structural properties of MoSe₂ and WSe₂.On this basis,few-layer MoSe₂ thin films with different stacking structures are grown.Various testing methods such as Raman spectroscopy,photoluminescence（PL）,and second harmonic generation（SHG）are used to explore the changes in the optical properties of MoSe₂ material on double-layer,triple-layer and continuous film with different stacking structures.Finally,the“one-step”chemical vapor deposition method is used to prepare MoSe₂/WSe₂ heterostructures,and the growth temperature of the heterostructure reaction and the amount of W source are changed to improve the preparation of MoSe₂/WSe₂ heterostructures.Multiple measurements are made to observe the phenomenon of PL quenching in the WSe₂region of the heterostructure and to obtain the principle of PL quenching in the MoSe₂/WSe₂ heterostructure.