Behaviour of the High‐Field Domains below the Voltage of the Nucleation Threshold

On the basis of the phenomenological theory it is shown that the high‐field domain in a Gunn diode does not annihilate if the applied voltage becomes lower than the threshold for domain nucleation. The dependence of the threshold for domain annihilation on the diode parameters is obtained. It is found that the domain annihilation amplitude is equal to half of the domain amplitude when the applied voltage corresponds to that at the beginning of the region of negative differential resistivity in the diode. The results obtained are important if an additional microwave voltage is applied, for example if the diode operates in a resonator.