Raman spectroscopy of annealed InAlAs quantum dots

Raman spectra of In0.65Al0.35As quantum dots (QDs) embedded between GaAlAs and GaP have been measured at room temperature. For the as-grown sample, in addition to the TO/LO modes from GaAs substrate, a weak broad peak appears from 165 cm-1 to 203 cm-1, corresponding to the interface mode of InAlAs QDs. The AlAs-like and GaP-like modes can be clearly seen at 382 cm-1. For the annealed samples, the AlAs and GaP-like modes disappeared, while the InAs-like modes become stronger, indicating strong intermixing between QDs and the matrix and the formation of uniform InGaAlAsP alloy.