Competition between strain and confinement effects on the crystalline quality of InAs/GaAs (001) quantum dots probed by Raman spectroscopy


K. Rezgui, Unité de Spectroscopie Raman, Faculté des Sciences de Tunis, Campus Universitaire, Elmanar, 2092 Tunis, Tunisia. E-mail:


Self-organized quantum dots (SOQDs) of InAs/GaAs (001) prepared at low growth temperatures have been carried out by Raman spectroscopy. The structural study performed on these samples using atomic force microscopy showed the presence of two families of quantum dots, and these results were confirmed by analysis of Raman spectra. The low temperature growth leads to smaller dots with nonuniform sizes. The disagreement between the lattice parameters violated the selection rules, and all Raman modes could be observed. SOQDs Raman spectrum shows contribution from the GaAs substrate, the wetting layer, InAs quantum dots and InGaAs alloys at InAs/GaAs interface. A spatial correlation model including the different vibration modes was used to adjust the experimental result. A good agreement of theoretical and experimental results was obtained. Copyright © 2012 John Wiley & Sons, Ltd.