InAs/GaAs quantum dots grown by metalorganic chemical vapor deposition

InAs quantum dots (QDs) have been grown by metalorganic chemical vapor deposition on exactly (001) oriented GaAs using the Stranski-Krastanow growth mode. The samples exhibit a high average dot density of 4 x 10(10) cm(-2) with no defects over macroscopic areas. The QDs show bright room temperature luminescence at around 1.1 eV. Vertical dot stacks consisting of up to 5 QD sheets with various GaAs separation layer thicknesses have been produced. Transmission eletron microscope images show pronounced QD ordering in the growth direction. For thin separation layers the dot luminescence is red shifted by similar to 70 meV for the stacked dots as compared to single dot sheets. A low threshold (100 A/cm(2) at 77 K) separate confinement heterojunction laser with a five-fold dot stack as an active medium operating at up to room temperature is demonstrated.