Lateral and vertical ordered one-dimensional InGaAs/GaAs quantum structures

Lateral and vertical ordered one-dimensional quantum structures, i.e. InGaAs/GaAs(001) quantum dot chains and quantum wires, have been obtained using molecular beam epitaxy. It was found that the InGaAs wires or dot chains sit on two-dimensional wetting layers and run along the [-110] direction, as the result of anisotropic strain and in-plane adatom diffusion. This anisotropic nature produces a model system for studying the electronic properties of one-, two-, and three-dimensional quantum confinements and related optical responses. The strain anisotropy is of importance in determining the electronic states of the quantum structures and the surrounding strained barrier. The strain-induced effects, such as change of band-gap and splitting of heavy–light hole states, were studied experimentally and theoretically. Optical anisotropy of these quantum structures is also discussed.