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.

[1] http://spectrum.ieee.org/semiconductors/devices/introducing-...