Optical phonons in self-assembled Ge quantum dot superlattices: Strain relaxation effects

Optical and acoustic phonon modes in self-organized Ge quantum dot superlattices

Raman scattering measurements were carried out in self-organized Ge quantum dot superlattices. The samples consisted of 25 periods of Ge quantum dots with different dot sizes sandwiched by 20 nm Si spacers, and were grown using solid-source molecular-beam epitaxy. Optical phonon modes were found to be around 300 cm, and a dependence of the Raman peak frequency on the size of dots was evidenced ...

Folded Acoustic Phonon Modes in Ge/Si Quantum Dot Superlattices With Different Periods

We present low-frequency Raman scattering measurements on self-assembled Ge/Si quantum dot superlattice samples grown by molecular beam epitaxy. The samples had different growth parameters, such as the number of periods, nominal thicknesses of Ge layers, and growth temperatures. Raman scattering peaks were observed in the low-frequency region (<30 cm ), which were attributed to the folded acous...

Longitudinal-optical-phonon-assisted energy relaxation in self-assembled CdS quantum dots embedded in ZnSe

The effect of plastic strain relaxation on the morphology of Ge quantum dot superlattices

A series of Ge quantum dot superlattices were prepared to study the relationship of the dot morphology evolution with the number of layers. Strain relaxation was observed in thicker films and the dots transited from broad size distribution to size equalization and eventually to broad size distribution again as a result of the generation of threading dislocations in the quantum dot superlattice ...

Raman scattering of folded acoustic phonons in self-assembled Si/Ge dot superlattices

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