Independent wavelength and density control of uniform GaAs/AlGaAs quantum dots grown by infilling self-assembled nanoholes.

Very low density growth of GaAs quantum dots in self-assembled nanoholes created by gallium droplet etching is demonstrated. The emission energy of the quantum dots can be accurately controlled by the GaAs deposition amount, from 1.8 to 1.6 eV, independently of the dot density which can be reproducibly controlled over the range 0.2-2×10-8 cm-2 by the gallium deposition rate. The ensemble full-width-half-maximum is <10 meV and single-dot linewidths of 40 μeV (limited by our spectral resolution) have been measured. Additionally, shallow mounds on the sample surface allow the buried GaAs/AlGaAs dots to be located. A simple method to reliably predict the emission energy based on the shape of the nanohole is presented. [ABSTRACT FROM AUTHOR]