Asimov wrote:

Hi,

I am thinking out loud about how the semiconductor LED evolved into
the laser diode, by exploiting the synchronized population increase
mechanism to generate monochromatic photon emission. Might it be
possible to scale down this electron mechanism to usable radio
frequencies and end up with a radio transmitting antenna that doesn't
require aerials? Might this device then be termed a radio diode?

LEDs don't emit coherent radiation. All your jumbo "RED" would do would
be to emit wideband noise.

--

Peter