Incorporation of sb in InAs/GaAs quantum dots

The formation of a quaternary InGaAsSb alloy is shown to occur in the core of epitaxial GaSb capped InAs/GaAs quantum dots emitting at 1.3 mu m. The existence of the four constituent elements is demonstrated by using spatially resolved low-loss electron energy loss spectroscopy and aberration-corrected high angle annular dark field scanning transmission electron microscopy. The intermixing process giving rise to the formation of this quaternary alloy takes place despite the large miscibility gap between InAs and GaSb binary compounds, and is probably driven by the existence of strain in the quantum dots. (c) 2007 American Institute of Physics.