Abstract
Two methods were studied to improve the optical quality of InAs quantum dot nanostructures grown in lattice-matched InAlGaAsInP double heterostructures of a center wavelength around 1.55 μm. By either inserting InAlAsInGaAs superlattices between the InAlGaAs waveguide and the upper InAlAs cladding layer, or depositing a tensile-strained InGaAs strain-balance layer after the quantum dot formation, the optical quality of the quantum dot samples is greatly improved and a strong room-temperature photoluminescence is observed. The InGaAs strain-balance layer can be used to reduce the overall strain of the heterostructure, which makes it possible to stack a large number of quantum dot layers to improve the uniformity of the dot size distribution and increase the optical gain volume for high performance photonic device applications. © 2005 American Vacuum Society.