All-Around Encapsulation of Silicene – Nanoscale Horizons (RSC Publishing)

Silicene or two-dimensional (2D) graphene-like silicon allotrope has recently emerged as a promising candidate for various applications in nanotechnology. However, few concerns involving its stability persist to date and need to be addressed to build devices that are compliant and competitive. Here, we present an all-around encapsulation methodology beyond the current state-of-the-art for silicene, typically sandwiched in between a capping layer (e.g., Al2O3) and the supporting substrate (e.g., Ag). In this framework, the insertion of one or two sacrificial 2D Sn layers enables the realization of different atomically thin encapsulation schemes, preserving the pristine properties of silicene while decoupling it from the growth template. On the one hand, the insertion of a 2D Sn layer at the bottom of silicene allows to remove the Ag substrate, stabilizing silicene which can be easily gated, for example, via the on the top oxide. On the other hand, a full 2D encapsulation scheme, where top and bottom faces of silicene are protected by 2D Sn layers, gives rise to an atomically thin and cm2-scaled membrane preventing degradation of silicene for months. Both schemes thus constitute an advancement for the silicene stability and encapsulation in ambient conditions, paving the way to further exploitation in flexible electronics and photonics.