Engineered Band Gap Pushes Graphene Closer to Displacing Silicon | Hacker News Reader

Engineered Band Gap Pushes Graphene Closer to Displacing Silicon

spectrum.ieee.org

53 pointsrbanffy13 comments

I wonder what kind of pressure we’re talking about to achieve that EV gap.

~2.3 GPa, the max mentioned in the paper, equates to around 20k atmospheres of pressure or around 300k psi.

That seems like an enormous amount of pressure. Can you put that into perspective, please?

Imagine 80 full sized SUVs stacked on top of each other, balanced on a 1” square metal rod.

I don't understand why they insist on fooling with carbon, when phosphorus forms nice sheets like graphene that are naturally semiconconducting.

It probably has a lot to do with appealing to the prejudices of grant committees.

Black phosphorus sheets are great but they are pretty hard to fabricate and they degrade very quickly when they come in contact with air (in a matter of hours). There have been various attempts to solve this, some of them successful (as far as we can tell from lab experiments, at least), but all solutions are in pretty early stages, and most of them seem pretty difficult to implement on an industrial scale. Basically, exposing the damn thing to anything but inert gases for more than a couple of hours destroys it. That's not too feasible today.

Can the computer in high pressure helium: better thermal conductivity then air. Or space applications.

The topic was replacing silicon. I'm sure there are niche applications for it, but having to seal everything helium-tight won't work for all use cases that are served by silicon chips.

The silicon is rarely exposed to air though. This is just a manufacturing issue, isnt it?

Good point. I have to confess that I didn't think about that. Then again I know very little of how much air a silicon chip is exposed to from manufacturing to actual use in a working system.

I suppose so, but it's easier to have your factory with ultra-clean air than have it with inert gases.

With submersion litography and the silicon wafers being in inert gas chambers for annealing to prevent oxidation faults I’m not sure that’s actually the case.

You usually don’t want to expose anything to oxygen especially something that is only a few nanometers thick so even if the base silicon does not oxidize (which afaik it does) once you begin the doping process not to mention laying down the metal layers oxygen is a big no no, the oxide layer that form on say copper coins is thicker than the copper layers in most ICs so I really don’t see oxygen as being viable medium during manufacturing.

Based on this it seems that when Oxygen is used it’s used as a purge gas https://www.globalspec.com/learnmore/materials_chemicals_adh...

Duh, the article speaks of Van der Waal forces instead of Van der Waals forces.

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