According to the article, if the device is small enough it doesn't require heliu...

bradyd · on June 23, 2014

"And we’ll have to devise proper packaging methods for these 1-atmosphere, helium-filled devices."

Actually it does require helium, but no vacuum.

Dylan16807 · on June 24, 2014

"For example, the mean free path of electrons in air under normal atmospheric pressure is about 200 nanometers, which on the scale of today’s transistors is pretty large."

It doesn't require helium; helium is just a bit better.

TylerE · on June 24, 2014

And vacuum, at least comparatively soft vacuum, isn't a big deal either. I've got functional vacuum tubes around here older than I am.