Robust electronic properties of monolayer BeO against molecule adsorption.

The stability of two-dimensional (2D) materials upon exposure to ambient conditions is significant for their applications. In this paper, the air stability of the BeO monolayer with and without vacancy defects is carefully studied via DFT calculations. Our results suggest high structural and electronic stability of BeO monolayers upon exposure to O 2 , N 2 , CO 2 and H 2 O even with Be vacancies. O vacancies are not favorable in free-standing BeO monolayers and can be easily healed by H 2 O or CO 2 adsorption. Due to the high stability, large band gap and atomic flat surface, BeO monolayers are expected to be an ideal encapsulation material for 2D electronic devices.