Photoluminescence of Self-Assembled InAs/GaAs Quantum Dots Covered by InAlAs and InGaAs Combination Strain-Reducing Layer

Self-assembled InAs/GaAs quantum dots covered by the 1-nm In_xAl_1-xAs (x = 0.2,0.3) and 3-nm In_0.2Ga_0.8As combination strain-reducing layer are fabricated, whose height can take up to 30-46 nm. The luminescence emission at a long wavelength of 1.33 μm and the energy separation between the ground and the first-excited state of 86 meV are observed at room temperature. Furthermore, the comparative study proves that the energy separation can increase to 91 meV by multiple stacking.