Self-assembling InAs and InP quantum dots for optoelectronic devices

Stranski-Krastanov growth in molecular beam epitaxy allows the preparation of self assembling InAs and InP quantum dots on GaAs and Ga0.52In0.48P buff er layers, respectively. InAs dots in GaAs prepared by slow growth rates an d low temperature overgrowth provide intense photoluminescence at the techn ologically important wavelength of 1.3 mum at room temperature. Strain indu ced vertical alignment, size modification and material interdiffusion for s tacked dot layers are studied. A blue shift of the ground state transition energy is observed for the slowly deposited stacked InAs dots. This is ascr ibed to enhanced strain driven intermixing in vertically aligned islands. F or very small densely stacked InP and InAs dots the reduced confinement shi ft causes a red shift of the ground state emission. The InP quantum dots sh ow intense and narrow photoluminescence at room temperature in the visible red spectral range. First InP/Ga0.52In0.48P quantum dot injection lasers ar e prepared using threefold stacked InP dots. We observe lasing at room temp erature in the wavelength range between 690-705 nm depending on the size of the stacked InP dots. (C) 2000 Elsevier Science B.V. All rights reserved.