Optical Properties and Post-Growth Annealing Effects of InAs Quantum Dots with a GaAs/InGaAs Strained Layer

Self-assembled InAs quantum dots (QDs) embedded in GaAs/InxGa(1-x)As strained layers with different In mole fractions were grown by using molecular beam epitaxy (MBE) and their optical properties were investigated by using photoluminescence (PL) spectroscopy. The InAs QDs were grown on GaAs(2 nm)/In(x)Ga(1-x)As(2 nm)(x10) strained layers with x = 0.1, 0.32 and 0.52 and were capped with the same strained layer. The PL peak positions of the InAs QDs were red-shifted by increasing the In mole fraction of the GaAs/In(x)Ga(1-x)As strained layer. As a result, the emission wavelength of the QDs embedded in the GaAs/In(x)Ga(1-x)As strained layer with x = 0.52 was about 1.27 mu m at room temperature. Compared to the PL spectra of the as-grown InAs QDs, the PL spectra of the InAs QDs grown on GaAs/In(0.1)Ga(0.9)As strained layers showed blue-shifts of about 100 meV with increasing annealing temperature up to 850 degrees C and significant enhancements of the PL peak intensity.