Pressure and electric field tuning of Schottky contacts in PdSe₂/ZT-MoSe₂ van der Waals heterostructure

A two-dimensional van der Waals (vdW) heterostructure (PdSe₂/ZT-MoSe₂) has been investigated through vdW corrected density functional theory. ZT-MoSe₂ acts as a Dirac material with an anisotropic Dirac cone and variable Fermi velocity (0.52–1.91 × 10⁵ ms⁻¹). The intrinsic Schottky barrier height can be effectively tuned by applying external pressure and an electric field to the heterostructure. The p-type Schottky barrier transforms into a p-type ohmic contact at pressure P ≈ 16 GPa. A positive electric field induces p-type ohmic contact while a negative electric field results in the transition from p-type Schottky contact to n-type Schottky contact, and finally to n-type ohmic contact at the higher values of the field. Moreover, the external positive (negative) electric field induces n-type (p-type) doping of ZT-MoSe₂ in the heterostructure and remarkably controls the charge carrier concentration. Our results demonstrate that controlling the external pressure and electric field in a PdSe₂/ZT-MoSe₂ heterostructure can result in an unprecedented opportunity for the design of high-performance nanodevices. (paper)