Research team succeeds in building transistors using silicene

February 3, 2015 by Bob Yirka, report

Schematics of silicene and its synthesis–transfer–fabrication process. a, Buckled honeycomb lattice structure of silicene. b, Silicene encapsulated delamination with native electrode (SEDNE) process, which includes the following key steps: epitaxial growth of silicene on crystallized Ag(111) thin film, in situ Al2O3 capping, encapsulated delamination transfer of silicene, and native contact electrode formation to enable back-gated silicene transistors. Credit: Nature Nanotechnology (2015) doi:10.1038/nnano.2014.325
( —A team of researchers with members from Italy and the U.S. has succeeded in building a transistor based on silicene, for the very first time. In their paper published in the journal Nature Nanotechnology, the team describes how they were able to get the notoriously finicky material to cooperate.

Silicene is where silicon is made in one atom-thick sheets—like graphene, it has proven to have fantastic electrical properties, which means it could be useful in , particularly as researchers continue to attempt to make faster or smaller computer chips. The problem with silicene is that it is very difficult to make and even more difficult to work with once a sheet is at hand. It has been only eight years since physicist Lok Lew Yan Voon published theories about how silicene would perform, and since then, various groups have tried creating the material, most finding little to no success. Those groups that have succeeded have found that getting the sheets to behave has been a serious hurdle to using it for any practical purposes. In this new effort, the researchers report that not only have they been able to create the material, but they have found a way to tame it enough to allow them to create tiny .

To get the nanosheets to cooperate the researchers first grew some sheets of it on a very slim base of silver that had been topped with . Once grown, the silicene sheet was peeled off its base and placed silver side up on a wafer. The silver was then fashioned to make electrical contacts allowing the sheet to be used as a transistor. The team reports that they built several such transistors and that they were stable when used in a vacuum. They also report, that thus far, the performance of the silicene has lived up to the theories that predicted its properties.

Though the team has technically created a transistor based on silicene, it is still not clear if such a process would be amendable to porting to a commercial application. Much more research will have to be done before that is determined. If it does work out, the team believes it would be easier to use in future electronics than graphene, because so much of chip design is already silicon based.

Explore further: Researchers prove stability of wonder material silicene

More information: Silicene field-effect transistors operating at room temperature, Nature Nanotechnology (2015) DOI: 10.1038/nnano.2014.325

Free-standing silicene, a silicon analogue of graphene, has a buckled honeycomb lattice1 and, because of its Dirac bandstructure2, 3 combined with its sensitive surface, offers the potential for a widely tunable two-dimensional monolayer, where external fields and interface interactions can be exploited to influence fundamental properties such as bandgap4 and band character5 for future nanoelectronic devices6, 7. The quantum spin Hall effect3, chiral superconductivity8, giant magnetoresistance9 and various exotic field-dependent states7 have been predicted in monolayer silicene. Despite recent progress regarding the epitaxial synthesis of silicene8, 9, 10 and investigation of its electronic properties11, 13, 14, 15, to date there has been no report of experimental silicene devices because of its air stability issue16. Here, we report a silicene field-effect transistor, corroborating theoretical expectations regarding its ambipolar Dirac charge transport17, with a measured room-temperature mobility of ∼100 cm2 V–1 s–1 attributed to acoustic phonon-limited transport18 and grain boundary scattering. These results are enabled by a growth–transfer–fabrication process that we have devised—silicene encapsulated delamination with native electrodes. This approach addresses a major challenge for material preservation of silicene during transfer and device fabrication and is applicable to other air-sensitive two-dimensional materials such as germanene2, 3, 4 and phosphorene19, 20. Silicene's allotropic affinity with bulk silicon and its low-temperature synthesis compared with graphene or alternative two-dimensional semiconductors suggest a more direct integration with ubiquitous semiconductor technology.

Press release

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5 / 5 (1) Feb 03, 2015
Graphene, Stanene, and now silicene. Whole new physics at work in single atom thick materials promising wonders. Good article.
Feb 03, 2015
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5 / 5 (1) Feb 03, 2015
It's a psychology thing and solely irrational one.

Had an epiphany on that, Zeph, and I think it explains much. People say we only use a fraction of our brain and I think I know which fraction it is. First, 'left-wing/right-wing' is one dimensional inside-the-box thinking—the very same box used to define and describe things like monetary economies, public relations, sexuality, power structures, and our 'human nature as an animal'. This box is a region of the brain about the size of an almond, called the hypothalamus. A right-wing brain uses frontal lobes rarely and without the benefit of much math and logic, to produce gems like, "it's not cheating—it's superior competition." A left-wing brain (altruistic) produces cogent assessments of reality that send right-wing brains straight to the amygdala, where they scream bloody terror, terror, terror; which stimulates everyone's hypothalamus, dragging us all down to their level.

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