Optical and Structural Properties of InAs Quantum Dots Emitting Near 1.5 $\mu$m Grown on a GaAs substrate with an ${\rm In}_{{\rm x}}{\rm Ga}_{1-x}$As Metamorphic Buffer Layer

The structural and optical properties of InAs quantum dots (QDs) grown on an ${\rm In}_{{\rm x}}{\rm Ga}_{1-{\rm x}}$ As metamorphic layer, with different x values, on GaAs substrates are presented. The results for various QD layer thicknesses and growth temperatures are reported. The density of the dots and their diameter increase as the In content in the metamorphic layer increases. For a layer of dots grown in a strained InGaAs quantum well, incorporated in a metamorphic layer with 30% In, room temperature photoluminescence emission at 1.57 $\mu$ m has been demonstrated.