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Silicene Discovered: Single-layer Silicon That Could Beat Graphene To Market
MrSeb writes "Numerous research groups around the world are reporting that they have created silicene, a one-atom-thick hexagonal mesh of silicon atoms — the silicon equivalent of graphene. You will have heard a lot about graphene, especially with regard to its truly wondrous electrical properties, but it has one rather major problem: It doesn't have a bandgap, which makes it very hard to integrate into existing semiconductor processes. Silicene, on the other hand, is theorized to have excellent electrical properties, while still being compatible with silicon-based electronics (abstract). For now, silicene has only been observed (with a scanning tunneling electron microscope), but the next step is to grow a silicene film on an insulating substrate so that its properties can be properly investigated."
May I guess the next few years of discoveries? Lithicene, Sodicene, Potassicene... well, I need hardly go on...
May I guess the next few years of discoveries? Lithicene, Sodicene, Potassicene... well, I need hardly go on...
And of course, Graphenicene!
So, Silicene has just been observed for the first time under a scanning tunnel microscope, has had its properties only theoretically proposed, and is hoped to be "as miraculous as Graphene". Nevertheless, the author of the article already believes that it will beat Graphene to the market? Sheesh! Are all headlines nowadays conjured up by a dedicated company full of marketing types?
"silicon — a material which will probably reach its physical limits in the next 5-10 years" Haven't they been saying that since 1980?
I would be a little concerned that the silicon mono-layer would grow a natural oxide very fast and thus consume the silicon?
The solution in a HEMT transistor is cool in this respect. It is using an un-doped IV-V semiconductor next to a highly doped layer and excess carriers will form a two-dimensional electron gas at the interface. The carriers will move along the surface of the un-doped semi-conducter that since it is un-doped have better mobility and fewer defects than doped material. It must be something along this property they try to re-create with a silicon mono-layer.
I thought they already figured out a way to induce a bandgap in graphene. Was I mistaken?
"Because of its unique physical properties, graphene, a 2D honeycomb arrangement of carbon atoms, has attracted tremendous attention. Silicene, the graphene equivalent for silicon, could follow this trend, opening new perspectives for applications, especially due to its compatibility with Si-based electronics. Silicene has been theoretically predicted as a buckled honeycomb arrangement of Si atoms and having an electronic dispersion resembling that of relativistic Dirac fermions. Here we provide compelling evidence, from both structural and electronic properties, for the synthesis of epitaxial silicene sheets on a silver (111) substrate, through the combination of scanning tunneling microscopy and angular-resolved photoemission spectroscopy in conjunction with calculations based on density functional theory."
This is from Phys Rev Letters (DOI: 10.1103/PhysRevLett.108.155501
they show reasonably convincing LEED (low energy electron diffraction) and STM (scanning tunneling microscope) images of the putative hexagonal close packed array of Si atoms.
It's only 5-10 years away like my permanent hair replacement procedure was 5-10 years ago. I'm still bald.
It makes me wonder if anything will ever replace silicon.
Good question. One of the great things about silicon from a device manufacturing perspective is that it forms an insulating oxide. Don't know if silicene will do that without compromising its desirable electronic properties. Maybe some of the modelers among us can tell what will happen to the electron structure when we start plugging oxygen atoms onto silicene?
You will have heard a lot about graphene, especially with regard to its truly wondrous electrical properties
In most press releases about graphene I read lately, the focus was on its mechanical properties, and the fact that it is conductive would be merely an (often convenient) side effect.
You are probably alluding to discovery that bi-layer or tri-layer graphene stacks can be induced to have a tunable bandgap... http://www.lbl.gov/msd/assets/docs/highlights/09-9FengWang_bilayer_graphene.pdf