Stabilization and Manipulation of Silicene via Interface Engineering

Silicene is the thinnest form of silicon, a two-dimensional (2D) layer with a quasi-planar (buckled) structure [1]. It is produced by epitaxy on substrates like (111)-terminated Ag in ultra-high vacuum conditions. Silicene has a chemically fragile nature for it is unstable on both of its faces. It undergoes quick environmental degradation on its top face if not encapsulated, and on its bottom face when stripped off from its epitaxial substrate. To address these issues, here we will report on stabilization schemes based on dry or wet chemical delamination starting from a both-side encapsulated silicene and ending up with a stable and durable silicene foil on a tested timescale of weeks [2]. We show that both-side encapsulation is made possible by Al₂O₃ capping of the top face [3] and interface engineering through the realization of a silicene-on-stanene heterostructure (with stanene being the 2D counterpart of tin) [4]. The silicene-stanene heterostructure proves to be a suitable layout where to capture unprecedented silicene-related features like local heat dispersion in silicene and its contribution to the optical reflectance of silver [5]. Finally, we show how the silicene foils can manipulated (e.g. streteched, bent, and transferred to secondary substrates) as desired therein displaying high mechanical flexibility and structural stability thus paving the way to their facile integration into diverse nanotechnology device platforms.<br/><br/>[1] A. Molle et al., Chem. Soc. Rev. (2018) 47, 6370.<br/>[2] C. Martella, et al, Adv. Funct. Mater. (2020) 30, 2004546.<br/>[3] A. Molle et al., Faraday Discuss. (2021) 227, 171.<br/>[4] D. S. Dhungana, et al., Adv. Funct. Mater. (2021) 31, 2102797.<br/>[5] E. Bonaventura et al., under review.