Controllable contact types of Janus MoSH and WSi2N4 van der Waals heterostructures via biaxial strain and external electric field

Abstract

Using the first-principles calculations, we construct the metallic Janus MoSH and semiconductive WSi2N4 van der Waals heterostructure (VHT) and investigate their interfacial characteristics under the effect of biaxial strain and external electric field. Due to vertical symmetry breaking, there are two kinds of stacking patterns: H or S surfaces in contact with the WSi2N4 monolayers. They are both p-type Schottky contact (ShC) whose p-type Schottky barriers are 0.92 and 0.17 eV, respectively. Under the regulation of the biaxial strain, the MoSH and WSi2N4 VHTs can transform among n-ShC, p-ShC and Ohmic contact (OhC). However, the modulation of the electric field only causes the transition from p-ShC to n-ShC for H surface contact or from p-ShC to OhC for S surface contact. Therefore, the biaxial strain is more effective in adjusting interfacial characteristics than the electric field. Our finding indicates that the Janus MoSH and WSi2N4 VHTs are adjustable for metal/semiconductor contact, which has good potential to apply in Schottky electronic devices.