SILICENE OVERVIEW

SILICENE ROADMAP

The production cost is the cost for industrial-scale production.Graphene was first isolated in 2004 by Novoselov and coworkers using mechanical exfoliation, or more commonly known as the scotch tape method. A piece of scotch tape was used to peel off single layers of graphene off of pencil lead (graphite). This work, and the subsequent characterization of graphene (i.e., verification of properties), led to Geim and Novoselov receiving the Nobel Prize for Physics in 2010.The same year, the group of W. A. de Heer produced epitaxial graphene on insulating silicon carbide (SiC) by thermal decomposition of the SiC at high temperature either in vacuum or in argon.

The mechanical exfoliation method produces high-quality graphene for research but cannot be scaled up for industrial production. However, growth of graphene on SiC can lead to industrial scale production for electronics applications. Two additional noteworthy fabrication methods include the surface graphitization on metals by chemical vapor deposition (possibly first achieved in 1967!), and chemical exfoliation (i.e., the separation of the graphene sheets by chemical means) from graphite powders. Growth on metals will require transfer to an insulating substrate for electronics applications. Chemical exfoliation tends to produce “dirty” samples though the process is typically low cost.

ELECTRONICS

The primary reason why graphene is attractive for making transistors is that the electron mobility could reach as high as 200,000 cm2/(Vs), whereas it is only ~1000 cm2/(Vs) for bulk silicon used in chips at room temperature.

This translates into much faster operating transistors and high-frequency operation. These have been demonstrated in the lab by IBM and others.

Silicene is predicted to have a mobility almost as large as for graphene. Hence, high-frequency silicene transistors are also expected.

The current graphene roadmap anticipates that a high-frequency graphene transistor might be commercialized during 2020-5. The reason for the 10-year delay is because the industrial production of graphene has not yet started and would be cost-prohibitive using current scientific knowledge.

Conversely, even though silicene was first made 8 years after graphene, it is anticipated that the first commercial high-frequency silicene transistor will precede graphene transistors by 1-2 years.

Given that the silicon industry is already existent, silicene is also expected to be the cheaper technology (versus Graphene).

The development of logic transistors is more heavily leaned towards silicene, since it has already been shown that silicene has an inherent advantage over graphene for the development of such: the ability to have a so-called band gap.