Coupling and interface effects in MoS2/WSe2 van der Waals nanostructure

Abstract

In this work we report the effects of the interface coupling, the effective mass, the Hartree and exchange–correlation potential on the total energy in quasi-2D MoS₂/WSe₂ van der Waals nanostructure. Analytical and numerical solutions of the total energy as a function of carrier density and effective mass are determined without self-consistent calculation. The calculation carefully indicates how the quasi-2D electron gas arises from the interface coupling between MoS₂ and WSe₂ layers. Moreover, the results showed that the width of the wave function and the length scale between the two materials’ interface decrease with increasing electron density while the corresponding ground state quantisation energy in the z-direction increases considerably. Furthermore, in MoS₂ layer with density n _s = 4 × 10¹² cm⁻² this additional separation is approximately 2 nm and 〈z〉 = 1 nm. Due to the disparity in effective mass of electrons and holes in MoS₂, the majority of the excess energy is absorbed as kinetic energy by electrons. The comparison with available experimental and DFT calculation indicates that the present work reproduces properly known results for MoS₂/WSe₂ interface.