As the title may suggest, I am in search of a LED that emits radio waves. Yes, radio. I have seen and heard of the wide spectrum of waves LEDs can produce, ranging from ultraviolet to infrared LEDs, but never of anything beyond that, for say, radio waves. Of course, it may sound as stupid as asking for a lamp emitting gamma ray on the shorter side, but this is practically possible, for so I believe. Also, I want to ask, do radio phototransistors exist?