This is one of the coolest things I have seen in a long time. I think the moment of transformation from digital to analog, or vice versa, is a fascinating moment to understand philosophically and practically. Here is the invention of vacuum tube technology at the nano scale. Fun not only for the advantage of extremely high frequency processing, but for the advantage of a2d transformation at nanoscale.
http://arstechnica.com/science/2014/06/nasa-melds-vacuum-tube-tech-with-silicon-to-fill-the-terahertz-gap/
And, here's the original link to the IEEE article, too:
http://spectrum.ieee.org/semiconductors/devices/introducing-the-vacuum-transistor-a-device-made-of-nothing