A nonsaturating velocity-field approximation for improved invariant domain analysis of Gunn effect devices

Experimentally, the excess domain potential of GaAs Gunn effect devices as a function of outside electric field does not exhibit as sharp a "knee" as predicted by the theoretical curves, based upon various approximations. A new approximation, based upon a nonsaturating velocity-field characteristic, predicts a softer "knee" when used in the invariant domain analysis and is closer to experimental results. The basis for this approximation, its use in invariant domain calculations, and experimental verification are described.