Electronic bandgap manipulation of monolayer WS₂ by vertically coupled insulated Mg(OH)₂ layers

Searching for novel two-dimensional (2D) materials with tunable electrical and optical properties is significant to develop next-generation multifunctional nanoscale optoelectronic devices. The new insulated Mg(OH)₂ is a promising and stable 2D material to construct heterojunction with transition metal dichalcogenides (TMDs). Here, WS₂-Mg(OH)₂ is experimentally designed and investigated. The similarity of lattice constants for the two materials is confirmed with selected area electron diffraction for the first time. By stacking Mg(OH)₂ layers on WS₂ monolayer, the Fermi level of WS₂ is distinctly elevated, making the WS₂-Mg(OH)₂ a promising heterostructure for constructing and optimizing tunable electronic devices. We also showed the adjustable transition properties with enhanced coupling effect by thinning the Mg(OH)₂ layers in the heterostructure. This study not only demonstrates the tunable Fermi levels and optical characteristics of WS₂-Mg(OH)₂, but also could promote the broad investigations of novel 2D materials for various optoelectronic device applications in nanoscale.