We carried out nonresonant and resonant Raman spectroscopy of quantum dots with diameter of . On the basis of our measurements and comparison with a recently developed theory, we were able to clarify the origin of the observed phonon peak shifts in quantum dots as compared to bulk . It has been found that the spatial confinement of optical phonons in -diameter dots leads to only few peak shifts. At the same time, we have demonstrated, that even a low-power ultraviolet laser excitation, required for the resonant Raman spectroscopy of , leads to strong local heating of the quantum dots, which results in very large redshifts of the optical phonon peaks. We have estimated from the observed redshift that the local temperature of the quantum dot ensemble is about . The obtained results are important for identification of phonon peaks in the Raman spectra of nanostructures.
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Research Article| January 25 2005
Origin of the optical phonon frequency shifts in quantum dots
Khan A. Alim;
Vladimir A. Fonoberov;
Khan A. Alim, Vladimir A. Fonoberov, Alexander A. Balandin; Origin of the optical phonon frequency shifts in quantum dots. Appl. Phys. Lett. 31 January 2005; 86 (5): 053103. https://doi.org/10.1063/1.1861509
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