Growth and Electronic Properties of Self-Organized Quantum Rings

A method is described which can be used to grow self-organized, nanoscopic InGaAs ring structures on GaAs substrate. Starting from self-organized InAs dots, the crucial step for the ring formation is a short annealing phase after the dots have been covered by a thin GaAs layer. Spectroscopic data are reviewed which show that the ring morphology can be preserved even after the InGaAs islands have been covered by additional cladding layers for the realization of electronically or optically active devices.