Tunable Schottky barrier and interfacial electronic properties in YX2–MX2 (Y=Ta, Nb; M=Mo, W; X=S, Se, Te) heterostructures

Abstract

Using first-principle calculations, metal–semiconductor (MS) contact of YX₂ (Y=Ta, Nb; X=S, Se, Te) and MX₂ (M=Mo, W; X=S, Se, Te) monolayers in the shape of YX₂–MX₂ van der Waals Heterostructures (vdWHs) are fabricated. Electronic structure, type of the Schottky contact and height of Schottky barrier at the interface of YX₂–MX₂ vdWHs are investigated. Stabilities of these systems confirmed via AIMD simulation and binding energies calculations. Electronic band structures confirm the metallic nature of YX₂–MX₂ MS vdWHs. Specific cases of the YX₂–MX₂ MS vdWHs have quite small (high) effective mass (carrier mobility), hence show potential for nanoelectronic devices. Workfunction and transfer of charges among the layers of YX₂–MX₂ MS vdWHs are also evaluated via electrostatic potential. A Schottky contact is established, while fabricating YX₂–MX₂ MS vdWHs. The calculated Schottky barrier height (SBH) show that YX₂–MX₂ (Y=Ta, Nb, M=Mo, W; X=S, Se, Te) vdWHs, initiate p-type of Schottky contact, while specifically, TaX₂–MTe₂ (M=Mo, W) and NbTe₂–MoS₂ and NbTe₂–WS₂ MS vdWHs initiate n-type of Schottky contact due to their higher Bn values. The SBH values are miniature compared to traditional MS contacts, but they are consistent with previous 2D based MS contacts. These observations indicates the potential of YX₂–MX₂ MS vdWHs for high-performance device application.