High quality InAs quantum dots covered by InGaAs/GaAs hetero‐capping layer

Abstract

Self-assembled InAs quantum dots with high performance were fabricated by molecular beam epitaxy via Stranski–Krastanov growth mode and InGaAs/GaAs hetero-capping growth. The size and shape of the dots were modified during the first GaAs capping layer, which plays an important role of a reduction in the inhomogeneous broadening. In particular, when the substrate temperature of the GaAs capping layer was 450 °C, the PL linewidth decreased to less than 20 meV. In order to reduce the residual strain in the InAs QDs and the capping layer, the InGaAs capping layer was additionally grown on the InAs dots covered by the first GaAs capping layer. As a result, the presented InGaAs/GaAs hetero-capping layer induced strong photoluminescence (PL) intensity, narrow PL linewidth and 1.3 μm light emission at room temperature.