Session D2 - Solid State Physics III.
ORAL session, Saturday morning, October 25
234, Sc
Collective impact ionization has been used to explain lock-on, an optically-triggered electrical breakdown occurring in some photoconductive semiconductor switches (PCSS's). An interesting aspect to lock-on is that it occurs in GaAs and InP PCSS's, but, so far, it has not been observed in Si or GaP. In this presentation, we discuss a rate equation implementation of collective impact ionization that leads to new insights both about electrical breakdown in insulating materials in general and about lock-on specifically. In this approach, breakdown is a steady state process controlled by competition between carrier generation and recombination. This leads to theoretical definitions for both the lock-on field and the breakdown field. Our results show that lock-on is a carrier-density dependent form of electrical breakdown which exists in principle in all semiconductors. We show that its observation or the lack thereof is dependent on the difference between the breakdown and lock-on fields. Results for GaAs, InP, Si, and GaP will be discussed.