High Optical Quality of InAs Quantum Dots with an InAlAsSb Strain-Reducing Layer

The effects of a thin InAlAsSb strain-reducing layer (SRL) on the optical properties of InAs/GaAs quantum dots (QDs) are studied. The adoption of the InAlAsSb SRL results in higher emission intensity and better size uniformity than its InAlAs counterpart. InAs QDs capped with the InAlAsSb SRL reveal a large state separation of 103 meV and thermal activation energy of 530 meV. The increase in radiative efficiency and temperature stability is attributed to high carrier confinement and reduced defects by the InAlAsSb SRL.