Three-Dimensional Interface Roughness in Layered Semiconductor Structures and Its Effects on Intersubband Transitions

A general model for treating the effects of three dimensional interface roughness (IFR) in layered semiconductor structures has been derived and experimentally verified. Configurational averaging of the IFR potential produces an effective grading potential in the out-of-plane direction, greatly altering the energy spectrum of the structures. IFR scattering self-energy is also derived for the general case; when IFR is strong, its scattering effect is shown to dominate over phonon interaction and impurity scattering. When applied to intersubband transitions, the theoretical predictions explain the experimental observation of the anomalous energy shift and unusual broadening of the ISB transitions in III-Nitride thin-layered superlattices.