Surface-oriented Gunn-effect oscillator

Coherent Gunn-effect oscillations at 3 Gc/s have been observed between coplanar contacts, with a 30 ¿m separation, on the surface of an epitaxial n-type GaAs wafer. By using this structure the difficulty of preparing thin GaAs wafers necessary for conventional Gunn-effect devices has been avoided; it should be possible to generate frequencies greater than 30 Gc/s using existing photolithographic processes.