Characterization of unintentionally-ordered superlattice resonant-tunneling diodes

In the molecular-beam-epitaxy growth of ternary and quaternary InGaAs and In(GaAl)As alloys on InP it is observed that the layer composition is ordered in the direction of growth. This ordering is caused by the nonuniform distribution of beam fluxes at the rotating substrate with an ordering period determined by the combined effects of growth rate and substrate rotation rate. The effect of the ordering is to produce a strained-layer superlattice whose properties can be inferred from the current-voltage characteristics of resonant-tunneling diodes. The physical and electrical characteristics of these rotation-induced superlattices are described utilizing several one-dimensional theoretical approaches to calculate the miniband structure and interpret the experimental data.<>