Strain distribution and optical phonons in InAs/InP self-assembled quantum dots

The strain distribution in self-assembled InAs/InP (001) quantum dots is calculated, using an atomistic valence force-field description. Two typical dot shapes are considered. Strain relaxation is found to depend much on the dot shape. From these modeling results we deduce the strain-induced phonon frequency shifts. Unlike confinement, strain induces large frequency shifts. The calculations agree well with experimental results obtained by Raman scattering. It is shown that alloying effects are small. Finally, we show that average strain values can be obtained experimentally if one combines longitudinal and transverse optical-phonon Raman scattering.