High pressure measurements and the "universal" scaling of impact ionization with bandstructure

We have investigated impact ionization in semiconductors under hydrostatic pressure (p), by measuring the avalanche breakdown voltage (V-b) in InAs, S i, GaAs and Ge. The sign of dV(b)/dp was determined by the dominant phonon scattering mechanism (polar or intervalley phonons). A quantitative compari son with simple theories gave information on the location in k-space of sec ondary electrons. Extending the analysis to the determination of V-b in wid e bandgap semiconductors revealed a simple linear relation between V-b and (E), a Brillouin-zone averaged energy gap.