Layer-dependent Schottky contact at TaX₂-BY (X = S, Se, Te; Y = P, As, Sb) van der Waals interfaces

The mechanical, thermal and dynamical stabilities, electronic structure, contact type, and height of the barrier at the interface of TaX₂ (X = S, Se, Te) and BY (Y = P, As, Sb) metal-semiconductor (MS) contact are investigated via first principles calculations. Binding energies, mechanical properties, phonon spectra and ab initio molecular dynamics (AIMD) simulations confirm the stabilities of these systems. TaX₂-BY (X = S, Se, Te; Y = P, As, Sb) MS van der Waals heterostructures (vdWHs) are found to be metal with a Schottky contact at the interface. Formation of the n-type Schottky contact at the interface of TaX₂-BY (X = S, Se, Te; Y = P, As, Sb) MS vdWHs favors electron conduction over hole conduction. Small (higher) effective mass (carrier mobility) make TaS₂-BSb, TaSe₂-BSb and TaTe₂-BSb MS vdWHs, potential candidates for high speed nanoelectronic applications. Bader charge analysis shows that at the interface of TaX₂-BY (X = S, Se, Te; Y = P, As, Sb) MS vdWHs, in TaX₂ (BP, BAs) the electrons transfer from the TaX₂ layer to the BP and BAs layer, while in TaX₂ (BSb) the electrons transfer from the BSb layer to TaX₂ layer.