has quite a bit on it checking out:

> He used these junctions to build solid-state versions of amplifiers, oscillators, and TRF and regenerative radio receivers, at frequencies up to 5 MHz, 25 years before the transistor. He even built a superheterodyne receiver.

That one calls them "negative resistance diodes" but I don't see how you can make a functional solid state amplifier and the like without it being a transistor.

Maybe Wikipedia needs some edits.