Carrier capture and relaxation in Stranski-Krastanow ${\mathrm{In}}_x{\mathrm{Ga}}_{1-x}\mathrm{As}/\mathrm{GaAs}\mathrm{}\left(311\right)B$ quantum dots

We have investigated the structure and optical properties of ${\mathrm{In}}_{0.6}{\mathrm{Ga}}_{0.4}\mathrm{As}/\mathrm{GaAs}\mathrm{}\left(311\right)B$ quantum dots (QD’s) formed by the Stranski-Krastanow growth mode during metal-organic chemical-vapor deposition. We find that $\mathrm{}\left(311\right)B$ QD structures display a higher energy QD luminescence emission and a stronger wetting-layer emission than (100) QD’s of similar diameter and density. Temperature-dependent photoluminescence (PL) measurements reveal shallow QD confinement energies and strong interaction between neighboring quantum dots. Longer PL rise times of the ground-state emission of $\mathrm{}\left(311\right)B$ QD’s compared to (100) QD’s are ascribed to the effect of differing numbers, energies, and level spacings of QD confined states on intersublevel relaxation mechanisms at low-carrier excitation densities.