Enhanced thermal stability and emission intensity of InAs quantum dots covered by an InGaAsSb strain-reducing layer

An InGaAsSb overgrown layer, i.e., strain-reducing layer (SRL), is adopted to increase the emission intensity of InAs quantum dots (QDs) and extend the emission wavelength to as long as 1.42μm. InAs QDs capped with InGaAsSb SRL also exhibit a thermal activation energy of 534meV, which is much higher than that of InAs QDs with an InGaAs SRL. The increase in luminescence efficiency and thermal stability is attributed to the improved carrier confinement of the GaAs∕InAs∕InGaAsSb heterostructure.