Long-wavelength emission in structures with quantum dots formed in the stimulated decomposition of a solid solution at strained islands

When an array of strained InAs nanoislands formed on a GaAs surface is overgrown by a thin (1-10 nm) layer of an indium-containing solid solution, stimulated decomposition of the solid solution is observed. This process causes the formation of zones of elevated indium concentration in the vicinity of the nanoislands. The volume of newly formed InAs quantum dots increases as a result of this phenomenon, producing a substantial long-wavelength shift of the photoluminescence line. This effect is enhanced by lowering the substrate temperature, and it depends weakly on the average width of the band gap of the solid solution. The indicated approach has been used successfully in achieving room-temperature emission at a wavelength of 1.3 μm.