The lock-on effect in electron-beam controlled gallium arsenide switches

A current lock-on at a constant voltage was observed in electron-beam controlled GaAs switches. Experimental results indicate that the lock-on current of the system is actually identical with the time-asymptotic dark current under double-injection conditions. It is shown that the pre-illumination of the sample with an ionization source does not influence the amplitude of the current but causes only a reduction in the time necessary to reach its final value. In particular, it is demonstrated that the initial highly resistive state is not an actual steady state but rather a transient phase characterized by a nonequilibrium distribution in the electron and hole trap occupation. Based on these experimental results, a scenario is developed which describes the lock-on effect in terms of current injection through the contacts and carrier trapping in deep intraband levels