Influence of the strain on the formation of GaInAs/GaAs quantum structures

The influence of the strain on the dot morphology of GaInAs quantum dots has been investigated. The strain was varied by the In content in GaInAs/GaAs quantum dots from 60% down to 30% by keeping the emission wavelength at about 900 nm at 10 K. Spectral properties are compared with morphological results determined by scanning electron and scanning transmission electron microscopy confirming a change of the dot geometry from circular to elongated shapes during an overgrowth process. These lowly strained quantum dot layers with enlarged dot sizes exhibit a reduced dot density of 6–9×109 cm−2 and a strongly enhanced oscillator strength, which make them very interesting for single quantum dot and cavity quantum electrodynamic experiments as well as for applications like single photon emitters.