▎ 摘　　要

A Schottky barrier, formed in the contact of a two-dimensional (2D) semiconductor and metal electrode, seriously degrades device performance. Herein, we propose a dipole-engineering strategy to regulate the electronic contact properties of a 2D polar SbX (X = P, As, Bi) and graphene (Gr) van der Waals interface. Owing to the mirror asymmetry of SbX, we construct seven vertical heterostructures in the form of X Sb-Gr and SbX-Gr. Tunable Schottky barrier height and contact type can be obtained by using different atomic terminals to contact with Gr. Based on the first-principles calculations, the dipole and its associated potential step are found to be responsible for the regulating effect. Moreover, owing to the remarkable properties of the SbBi-Gr heterostructure, such as Ohmic contact and low tunneling barrier, we design an optoelectronic field-effect transistor, which exhibits considerable responsivity (0.089 AW(-1)) and external quantum efficiency (28.57%). Our findings further confirm that regulating the electronic contact properties by the dipole in the heterostructure is a feasible strategy, which provides meaningful guidance for designing high-performance electronic and optoelectronic devices.