This paper was published in 2012. The abstract uses the term "nano" three times, and it appears twice in the title. Bad sign. They made a small transistor gate in a standard semiconductor wafer fab. The gate has an air gap, but charges make it across the gap. This is called a vacuum-channel transistor, and they've been known for years. It's more like a MOSFET than a triode. Speeds are currently up to 0.5THz.
There are better articles.[1]
It's a low-power device, so it's not going to power terahertz radars. Fast logic, maybe, but that's a ways off.
I didn't notice it until after I'd read it, but this is from 2012. Does anyone know of an update on this particular technology or approach? Has it yielded any progress after nearly three years?
What KORG's got there is a lot more like a traditional vacuum tube than what's being described in the 2012 article. It's primarily intended for audio equipment that'd traditionally have used a tube anyway.
Don't get your hopes up. There has been discussion of variants of this setup for almost 40 years now. None has made it to market, as far as I am aware.
> My understanding is that electrons wouldn't move at all in a vacuum because they require a conductor.
Electrons can propagae in the absense of a medium, in addition to within a conductor. You might thinking of their motion through conductors relative to insulators; but in that comparison, electrons don't (readily) move through insulators because they are impeded.
In the particular case of a vacuum tube, the electrons are freed from the surface of the filament, where they travel through the vacuum in a tube and are attracted via electrostatic forces, to the positively charged plate at the top of the tube.
Could the absence of a medium also be considered an insulator? The description of Thermionic emission on Wikipedia (http://en.m.wikipedia.org/wiki/Thermionic_emission) seems general enough that things like rubber and vacuums are both insulators in some sense.
"Insulator" usually means "made of insulating material", and a vacuum is not made of material. :-)
Language is ambiguous, so it's important when asking questions like this to be really clear about what you mean by terms.
In particular: "insulator" is a term of convenience that groups together materials of sufficiently low conductivity under fairly normal conditions. What constitutes "sufficiently low" and "fairly normal" are both highly context dependent. Heat anything up enough and it'll become a conductor (it'll also become a plasma). If you use a term like "insulator" without keeping all this in mind it'll produce some pretty weird results.
So you can answer this question all kinds of ways. In normal high-voltage parlance, vacuums are considered insulators. But unlike insulating materials, which are full of electrons that can't move, vacuums are insulators purely because they don't contain any electrons.
If you inject electrons, the vacuum becomes a conductor... or at least the electrons do. After all, a vacuum is an absence of matter, and where there is an electron there is matter, so where there is an electron there is not a vacuum...
Sure. Vacuum is an insulator until you exceed its breakdown voltage, just like other insulators. Electricity will go through a vacuum just like it will go through a polyester film or whatever.
Thermionic emission just refers to releasing electrons from the surface of a material by heating up that material (which is what happens in a vacuum tube). But it doesn't specifically deal with what happens to the electrons after they leave the surface of the material. I am not sure what part of the wikipedia article you are referring to – the word "insulator" isn't used anywhere in the article.
There are better articles.[1]
It's a low-power device, so it's not going to power terahertz radars. Fast logic, maybe, but that's a ways off.
[1] http://spectrum.ieee.org/semiconductors/devices/introducing-...