Temperature dependence of ionization rates in AlxGa1-xAs

Abstract

The ionization rates in AlxGa1-xAs have been measured in a temperature range from 77[deg]K to 373[deg]K for samples with various Al content. The results showed that the ionization rates decrease with both the Al content and temperature at a given electric field. A deviation from exp(1/E2) field dependence is observed for the sample with the highest Al content at lower temperatures. By fitting the data into the modified Baraff's plot, [lambda], the optical phonon mean free path was determined at four different temperatures. Assuming [lambda] = [lambda]0 tanh ([epsilon]r/2kT), [lambda]0, the high-energy low-temperature asymptotic limit of the mean free path was evaluated. The temperature dependence of [lambda] and the compositional dependence of [lambda]0 are discussed.