Fabrication and optical properties of GaAs/AlGaAs quantum dot grown in tetrahedral-shaped recesses on GaAs (1 1 1)B substrates by MOVPE

GaAs/AlGaAs quantum dots were grown in tetrahedral-shaped recesses (TSRs) on GaAs View the MathML sourceB substrates at 850°C by metalorganic vapor-phase epitaxy on the bottom View the MathML sourceB regions of the TSRs. As the AlGaAs barrier layer became thicker, a trench-like region comprised of View the MathML source and View the MathML source vertical sidewalls formed at the bottom region of the TSR. A View the MathML source-wide and View the MathML source-thick GaAs quantum dot was formed at the bottom of the trench-like region. The luminescence from GaAs layer at only the View the MathML sourceB bottom region of the TSR was confirmed by cathodoluminescence image observation. By micro-photoluminescence observation a narrow line from the bottom region was observed at 1.5511 eV and the luminescence from higher-energy states was observed. The calculation for a View the MathML source quantum box revealed that these energy states reflected both the lateral and vertical quantum confinements.