Self-organised quantum dots as dislocation filters: the case of GaAs-based lasers on silicon

The use of multiple layers of self-organised InAs quantum dots as a very effective dislocation filter is demonstrated. In0.5Ga0.5As/GaAs quantum dot lasers grown directly on silicon substrates with the InAs quantum dot buffer layer exhibit substantially reduced threshold currents (Jth∼900 A/cm2), compared to devices grown on silicon without the dot buffer layer (Jth≥1500 A/cm2).