Electronic states in strained cleaved-edge-overgrowth quantum wires and quantum dots

The electronic properties of cleaved-edge-overgrowth (CEO) strained T-shaped quantum wires and twofold CEO quantum dots are calculated in the presence of strain induced by lattice mismatch. Potential modifications of growth morphology due to strain are discussed. The anisotropy of the elastic constants causes the band edges in (001) and (110)-oriented layers to be different. Using effective-mass theory, we find electrons to be localized in asymmetric strained T-shaped quantum wires, whereas holes are repelled. Coulomb interaction can induce localization of excitons. For twofold CEO quantum dots, bound states are expected only when (compressive) strain effects are small. In our calculation image charge effects are properly taken into account. Numerical examples are presented for the ${\mathrm{In}}_{0.2}{\mathrm{Ga}}_{0.8}\mathrm{A}\mathrm{s}/\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}$ system.