Probing growth-related disorder by high-field transport in semiconductor superlattices

We investigate the influence of imperfections in the sample growth on the electrical transport in doped superlattices. While structurally perfect samples should exhibit a regular set of current branches, our theoretical investigations show that local fluctuations of the sample parameters in the growth direction strongly modulate the branches of the current-voltage characteristic. A comparison with experimental data allows an estimate of the range of doping fluctuations between 3% and 10%. The disorder strongly affects the frequency as well as the mode of the self-oscillations of the current.