Theory of electron impact ionization including a potential step: Application to GaAs-AlGaAs

A Monte Carlo simulation of the electron impact ionization enhancement by a Kronig-Penney superlattice is presented. The results are compared to measured ionization coefficients of a GaAs/AlGaAs superlattice structure. The theory confirms the predicted and measured enhancement of the electron ionization rate. A quantitative fit of the theoretical data to the experimental results suggests a conduction-band offset in the GaAs/AlGaAs system which is roughly equal to 75 percent.