Segregation in InGaAs/GaAs Stranski-Krastanow layers grown by MOCVD

Emanuela Piscopiello (1, 2) , Andreas Rosenauer (3) , Adriana Passaseo (4) , Eduardo Haroldo Montoya Rossi (5) , Gustaaf van Tendeloo (5)

1 Materials and New Technologies Unit Composite and Nanostructured Materials Section
2 EMAT
3 IFP
4 NNL
5 EMAT

Using quantitative high resolution transmission electron microscopy we studied the chemical morphology of wetting layers in InGaAs/GaAs quantum dot structures which were optimised for applications to optical devices operating around 1.3 ƒÝm. The samples are grown by low-pressure metal-organic chemical vapour deposition on GaAs substrates. Indium concentration profiles of the wetting layers are evaluated with the composition evaluation by the lattice fringe analysis method. The profiles reveal a clear signature of segregation. A fit of the profiles with the Muraki model for segregation (K. Muraki et al., Appl. Phys. Lett. 61 (1992), 557) reveals a segregation efficiency of R=0.65¡Ó0.05 at the growth temperature of 550 ¢XC, which is significantly lower than segregation efficiencies observed in samples grown by molecular beam epitaxy at similar temperatures.

Mots clés: Physical Sciences

Emanuela Piscopiello, Andreas Rosenauer, Adriana Passaseo, Eduardo Haroldo Montoya Rossi, Gustaaf van Tendeloo. Segregation in InGaAs/GaAs Stranski-Krastanow layers grown by MOCVD. Philosophical Magazine, 2005, 85 (32), pp.3857-3870. ⟨10.1080/14786430500269402⟩. ⟨hal-00513590⟩