Transient changes in material conductivity due to impact ionisation in a Gunn-effect domain

An interesting phenomenon is reported which occurs when a long sample of GaAs containing a high-field domain is subjected to an increased level of drive during part of it first cycle. Under such conditions there is produced locally, at the position where the domain is situated when the overdrive is applied, an increase in the free-carrier concentration, which then decays relatively slowly (approximately 1 ¿s). The effect is very similar to that first observed by Owens and Kino and ascribed by them to the generation of a second stable domain while the first is in transit through the device.