Chemical routes to modify, uplift, and detach a silicene layer from a metal substrate

Experimental studies have shown that honeycomb silicene layers can grow on various metal substrates. Here we demonstrate using first-principles calculations that hydrogenation and calcium intercalation can be employed to break bonds between a silicene overlayer and a silver surface. The end result of the former process is the creation of a silicane mono-layer, a wide band-gap semiconductor. In this way, the Si overlayer can eventually be etched away, in agreement with pertinent experiments. Ca intercalation, on the other hand, lifts the silicene sheet up without destroying its sp(2) honeycomb bonding. Both approaches augment thus the functionalities of silicene overlayers by creating two-dimensional materials with distinct properties.