First-principles study of two-dimensional MoSi2N4/WSe2 heterostructure
The experimentally newly synthesized MoSi2 N4(MSN)has attracted much attention due to its unique septuple-atomic layers structure and electronic properties.In this work,a two-dimensional MSN/WS hetero-structure stacked by a two-dimensional MSN vertically with a two-dimensional WSe2(WS)is constructed and its electronic properties is calculated based on the first-principles calculations,which exhibits direct gap semi-conductor properties with a band gap of 1.46 eV and type-Ⅰ band alignment.A weak built-in electric field from the charge depletion layer MSN to the charge accumulation layer WS exists at the interface of the hetero-structure.Finally,the two-dimensional MSN/WS heterostructure is modulated by applying the biaxial strain.It is found that under the positive biaxial strain,the MSN/WS heterostructure maintains the original direct band gap semiconductor and type-Ⅰ band alignment properties.Under the negative biaxial strain,the MSN/WS hetero-structure changes from the original direct bandgap semiconductor to the indirect band gap semiconductor,and when the applied negative biaxial strain reaches-6％and-8％,the type-Ⅰ band alignment changes to the type Ⅱ band alignment.
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