A computational study of monolayer hexagonal WTe2 to metal interfaces

Abstract

Monolayer (ML) hexagonal (2H) WTe2 is predicted to be the best channel material of tunnel field effect transistor (TFET) and metal–oxide–semiconductor field effect transistor (MOSFET) among ML transition‐metal dichalcogenides. Actual devices based on 2H WTe2 typically have a contact with metal. We explore for the first time the interfacial properties between ML 2H WTe2 and Sc, Ti, Pd, Pt, Ag, and Au by using ab initio electronic structure calculation and ab initio quantum transport simulations. The energy bands of ML 2H WTe2 on Sc, Ti, Pd, and Pt substrates are destroyed strongly due to strong adhesion of ML 2H WTe2 with metal substrates, and ML 2H WTe2–Sc, −Ti, −Pd, and −Pt systems are regarded as new metallic materials. Weak adhesion is formed between ML 2H WTe2 and the Ag and Au surfaces, with the electronic energy band of ML 2H WTe2 being identifiable. Ag and Au form n‐type Schottky contact with ML 2H WTe2 at the vertical direction with electron Schottky barrier height (SBH) of 0.24 and 0.49 eV, respectively. In contrast, Pd, Pt, and Ti form p‐type Schottky contact with ML 2H WTe2 in the lateral direction with hole SBH of 0.26, 0.40, and 0.63 eV, respectively. Our study not only presents a theoretical insight into the ML 2H WTe2–metal interfaces but also help in ML 2H WTe2 based device design.