Structural and optical properties of InAs quantum dots in AlGaAs matrix

Structural and optical properties of InAs quantum dots (QDs) grown in a wide-bandgap Al 0.3 Ga 0.7 As matrix is studied. It is shown that a high temperature stability of optical properties can be achieved owing to deep localization of carriers in a matrix whose band gap is wider than that in GaAs. Specific features of QD formation were studied for different amounts of deposited InAs. A steady red shift of the QD emission peak as far as ∼1.18 µm with the effective thickness of InAs in Al 0.3 Ga 0.7 As increasing was observed at room temperature. This made it possible to achieve a much higher energy of exciton localization than for QDs in a GaAs matrix. To obtain the maximum localization energy, the QD sheet was overgrown with an InGaAs layer. The possibility of reaching the emission wavelength of ~1.3 µm is demonstrated.