Silicene is the thinnest form of silicon. It is metallic, has graphene-like mobile carriers and can behave like a semiconductor. The wonder material could lead to even smaller electronics but challenges remain in this review published in the Science and Technology of Advanced Materials.
Scientists in Japan compared the properties of a hypothetical freestanding one-atom-thick layer of silicon to a similar sheet developed on a metal substrate. Although promising, this second “epitaxial” form shows important differences. Turning the hypothetical material into a reality still remains a major challenge, 20 years after it was first reported.
In 1994, scientists published their first theoretical report on the thinnest possible form of silicon. Among many other uses, silicon is incorporated as a semiconductor in integrated circuits, the basis of most computers.
But it was only ten years later in 2004, when another material, graphene, was reported, that scientists started showing a real interest, and eventually named the material, “silicene”.
Graphene is a one-atom-thick layer of carbon that has been shown to host the fastest carriers of electricity yet found. Compared with silicon, however, graphene is not a semi-conductor because it can’t switch between conducting and not conducting states. This makes it very difficult to apply it in a switching device such as a transistor.
This is why silicene is so exciting. In its freestanding form, this one-atom-thick layer of silicon atoms has graphene-like mobile carriers as well and is metallic. On the other hand, for instance by applying strain or an electric field, it could also be turned to behave like a semiconductor.
This is because the structure could be easily modified or switched on the atomic scale. In addition, it would be compatible with already existing silicon-based circuitry. This is envisaged to lead to the development of even smaller electronics than those currently on the market.
Because of its exciting potential, the experimental demonstration of the existence of silicene was highly anticipated. In 2012, several groups reported successfully developing “epitaxial” silicene: silicene sheets formed on metallic substrates.
A team of Japanese scientists compared the characteristic properties of theoretical freestanding silicene to epitaxial silicene they had produced on a zirconium diboride substrate. They found that the crystal structure of epitaxial silicene was strongly influenced by its metal substrate, thus resulting in electronic properties different from those predicted for the hypothetical freestanding form.
The synthesis of freestanding silicene remains a major challenge and many of the properties of its epitaxial form are not yet fully understood. However, the team of Japanese scientists joined by a few other groups worldwide will further work on the understanding of the formation mechanism of epitaxial silicene and its interaction with the substrate. Based on the deep understanding of this matter, present and future work is anticipated to result in the required developments such as the formation of silicene on an insulating platform and its successful encapsulation. This would then lead to practical applications of the material.
For further information contact:
Associate Professor Yukiko Yamada-Takamura
School of Materials Science
Japan Advanced Institute of Science and Technology
Yukiko Yamada-Takamura and Rainer Friedlein 2014 Sci. Technol. Adv. Mater. 15 064404 doi:10.1088/1468-6996/15/6/064404
An innovative high-performance material: biofibers made from green lacewing silk
20.01.2017 | Fraunhofer-Institut für Angewandte Polymerforschung IAP
Treated carbon pulls radioactive elements from water
20.01.2017 | Rice University
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
20.01.2017 | Life Sciences
20.01.2017 | Physics and Astronomy
20.01.2017 | Materials Sciences