Effects of external stress on the electronic structure and optical properties of [001]- and [111]-growth-axis semiconductor superlattices

Publisher Website
Google Scholar
Abstract
We analyze the effects of an external compressive stress on the electronic structure of [001]- and [111]-growth-axis semiconductor superlattices. Lattice-matched and strained-layer superlattices are considered. We treat cases where the external stress is applied in a direction perpendicular to the growth axis of the superlattice. In the case of [001]-growth-axis superlattices, the application of a stress perpendicular to the growth axis can cause a strong admixture of the light- and heavy-hole states, resulting in transition energy shifts that are nonlinear functions of the magnitude of the applied stress. This behavior has its physical origin in deformation-potential effects described by the strain Hamiltonian. Additional effects can arise in [111] strained-layer superlattices where the application of an external stress can also cause a modulation of the internal strain-induced electric fields in addition to deformation-potential effects. These internal electric fields arise because of the piezoelectric nature of III-V zinc-blende-structure semiconductor materials. Since the strain-induced internal electric fields are proportional to the off-diagonal components of the internal strain tensor, they vanish in strained-layer superlattices grown along the [001] orientation.