Insights into the Mechanical and Electrical Properties of a Metal-Phosphorene Interface: An Ab Initio Study with a Wide Range of Metals.

Finding a metal contact with higher interface adhesion and lower contact resistivity is a major challenge in realizing 2D material-based field-effect transistors. The commonly used metals in the semiconductor industry have different interface chemistry with phosphorene. Although phosphorene FETs have been fabricated with gold, titanium, and palladium contacts, there are other metals with a better interface. In this work, using DFT, a systematic ab initio study of metal-phosphorene interfaces is carried out for a set of 18 potentially suitable metals with different resistivity, electronegativity, and work-function. The interface between these metals and phosphorene is studied to identify factors responsible for mechanical and electrical behavior of the metal contacts. The work of separation is calculated to measure the adhesion strength of the metal contacts, while the density of states, Schottky barrier height, tunnel barrier height, and the mid-interface charge density calculations are performed to analyze the electrical behavior. Both mechanical and electrical performance of the metal contacts are linked to the interface chemistry. Many important observations which deviate from the general trend are reported and explained.