Using quantitative high-resolution transmission electron microscopy we studied the chemical morphology of wetting layers in InxGa1-xAs/GaAs quantum dot structures which were optimized for applications to optical devices operating around 1.3 mu m. The samples are grown by low-pressure metal-organic chemical vapour deposition on GaAs substrates. The In concentration profiles of the wetting layers are evaluated with the composition evaluation by lattice fringe analysis method. The profiles reveal a clear signature of segregation. A fit of the profiles with the Muraki et al. model for segregation reveals a segregation efficiency R = 0.65 +/- 0.05 at the growth temperature of 550 degrees C, which is significantly lower than segregation efficiencies observed in samples grown by molecular beam epitaxy at similar temperatures.
Segregation in InxGa1-xAs/GaAs Stranski-Krastanow layers grown by metal-organic chemical vapour deposition.
Passaseo A;
2005
Abstract
Using quantitative high-resolution transmission electron microscopy we studied the chemical morphology of wetting layers in InxGa1-xAs/GaAs quantum dot structures which were optimized for applications to optical devices operating around 1.3 mu m. The samples are grown by low-pressure metal-organic chemical vapour deposition on GaAs substrates. The In concentration profiles of the wetting layers are evaluated with the composition evaluation by lattice fringe analysis method. The profiles reveal a clear signature of segregation. A fit of the profiles with the Muraki et al. model for segregation reveals a segregation efficiency R = 0.65 +/- 0.05 at the growth temperature of 550 degrees C, which is significantly lower than segregation efficiencies observed in samples grown by molecular beam epitaxy at similar temperatures.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
