Silicine, the new graphene?

Researchers at the University of Wollongong have successfully fabricated single-atom-layer silicine. The material could be used to develop faster computer chips, more practical and efficient solar cells, improved medical technologies and vehicle and aircraft parts. 

Silicene is similar to graphene in that it is a single atom thick and has the same honeycomb structure. Theoretical calculations have predicted that silicene would contain exciting properties that could be used in a range of applications. However, its complicated formation chemistry and physics makes the fabrication of this material extremely difficult.

The UOW research team (including Dr Yi Du, Dr Xun Xu, Dr Stefan Eilers, Dr Germanas Peleckis, Professor Xiao Lin Wang and Professor Shi Xue Dou from the Institute for Superconducting and Electronic Materials (ISEM), located at the UOW’s Australian Institute for Innovative Materials facility) is one of a small number of teams around the world who have successfully fabricated silicene. ISEM Director, Professor Shi Xue Dou said that being the first group to fabricate silicene in Australia was a tremendous breakthrough.

“Silicene is an exciting new material, rich in physics and chemistry sciences and possible applications, and it is fantastic that we have been able to fabricate it here. We are also the first group to perform Raman spectroscopy investigation on the phonon modes for the first time in the world using scanning near-field optical microscopy,” Professor Dou said. A phonon is a collective excitation in a periodic, elastic arrangement of atoms or molecules in condensed matter such as solids and some liquids.

The research team noted that this work would not have been possible had it not been for the three-chamber, low-temperature scanning tunnelling microscope (STM), the first of its type in Australia, which allows researchers to undertake surface imaging at atomic level. The purchase of the microscope was possible after the team at ISEM and their collaborators were successful in securing a $2,500,000 grant from the Australian Research Council.

“The scanning tunnelling microscope allows us to both examine and manipulate materials at an atomic level. This enables us to discover new properties with the aim of maintaining those properties as we scale the materials up from the nanoscale to a scale that would be useful in manufacturing and production,” Professor Dou said.

The research team will continue their efforts to advance their knowledge of the fundamental properties of silicene and how they can harness its properties for use in applications from nanoelectrics through to solar energy applications.

This team has also demonstrated the molecular gear for a nanomachine and tuning the interaction within a molecular layer and between a molecular layer and substrate with light. The team has actively collaborated with researchers from the University of Queensland and the Institute of Physics of Chinese Academy of Sciences.