Stability and universal encapsulation of epitaxial Xenes

In the realm of two-dimensional materials framework, single-element graphene-like lattices, known as Xenes, pose several issues concerning their environmental stability with implication in their use for technology transfer to a device layout. In this Discussion, we scrutinize the chemical reactivity of epitaxial silicene, taken as a case in point, in oxygen-rich environments. Oxidation of silicene is detailed by means of a photoemission spectroscopy study upon carefully dosing molecular oxygen in vacuum and subsequent exposure to ambient conditions, showing different chemical reactivity. We therefore propose a sequential Al2O3 encapsulation of silicene as a solution to face degradation proving effectiveness by virtue of the interaction between silicene and silver substrate. Based on this direction, we generalize our encapsulation scheme to a large number of metal-suported Xenes by taking the case of epitaxial phosphorene-on-gold into account.