Comparative study of InAs quantum dots with different InGaAs capping methods.

The authors have used cross-sectional scanning tunneling microscopy to examine strain relaxation profiles of InAs quantum dots with In0.33Ga0.67As layers overgrown by three distinct capping methods. A statistical analysis of strain relaxation profile allowed them to infer that the long wavelength emission (>1.3 μm) of InAs quantum dots capped with sequential GaAs/InAs binary growth is mainly due to a weaker quantum confinement effect. This particular capping method is better than the traditional molecular beam epitaxy with simultaneous In/Ga/As deposition, and much better than a capping method with separated Ga deposition followed by As and InAs growth. [ABSTRACT FROM AUTHOR]