Silicene promise for electronics

Thick multilayers of silicene can remain intact when exposed to air for at least 24 hours, making it a promising material for the electronic industry. Silicene is made from single, honeycomb-shaped layers of silicon which are just one atom thick. It must be made in a vacuum to avoid contact with oxygen – which destroys the single layer structure – and grown on a surface matching its natural structure, namely silver. It can be transformed from a 2D to 3D material by stacking single layers on top of each other, but will revert back to silicon if too many layers are added, since the silicon structure is more stable. In this new study, published in 2D Materials, a team of researchers from France and Italy created silicene from a wafer of silicon heated to 1470K. The high temperature forces single silicon atoms to evaporate and land on the silver substrate forming a single layer. The team deposited a total of 43 monolayers of silicene on the substrate, which was kept at 470K. Researchers noticed these monolayers had a very thin layer of oxidation on the multi-layered stack; this oxidation actually helped to preserve the integrity of the stack, acting like a protective layer. The stack remained preserved for at least 24 hours in open air, at which point the researchers used X-ray diffraction and Raman spectroscopy to look for the unique finger prints of multilayer silicene, thus confirming the material was indeed silicene and not ordinary silicon. “These results are significant as we have shown that it is possible to obtain a silicon-based 2D material, which up until a couple of years ago was deemed inconceivable,” said lead author Paola De Padova, from Consiglio Nazionale delle Ricerche in Italy "Our present study shows that multi-layered silicene is more conductive than single-layered silicene, and therefore opens up the possibility of using it throughout the silicon microelectronics industry. In particular, we envisage the material being used as gate in a silicene-based MOSFET, which is the most commonly used transistor in digital and analogue circuits. The researchers are now studying the possibility of growing multi-layered silicene directly onto semiconductor substrates to explore the joint superconducting properties. 24 h stability of thick multilayer silicene in air