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Raman Spectroscopy of Ge Nanocrystals Grown by Self-Organization Processes

Published online by Cambridge University Press:  15 February 2011

A. Stella ,
C. E. Bottani ,
P. Cheyssac ,
R. Kofman ,
P. Milani  and
P. Tognini
A. Stella
Affiliation:
Istituto Nazionale per la Fisica della Materia, Dipartimento di Fisica “A. Volta”, Università di Pavia, Via Bassi 6, 27100 Pavia, Italy
C. E. Bottani
Affiliation:
Istituto Nazionale per la Fisica della Materia, Dipartimento di Ingegneria Nucleare, Politecnico di Milano, Via Ponzio 34/3, 20133 Milano, Italy
P. Cheyssac
Affiliation:
Laboratoire de Physique de la Matière Condensée, URA 190, Université de Nice Sophia Antipolis, Nice Cedex, France
R. Kofman
Affiliation:
Laboratoire de Physique de la Matière Condensée, URA 190, Université de Nice Sophia Antipolis, Nice Cedex, France
P. Milani
Affiliation:
Istituto Nazionale per la Fisica della Materia, Dipartimento di Fisica, Università di Milano, Via Celoria 16, 20133 Milano, Italy
P. Tognini
Affiliation:
Istituto Nazionale per la Fisica della Materia, Dipartimento di Fisica “A. Volta”, Università di Pavia, Via Bassi 6, 27100 Pavia, Italy
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Abstract

We report Raman spectroscopy measurements on Ge nanocrystals with average radii ranging from about 65 Å down to 10 Å (with a size dispersion lower than 20 %).

Ge has been deposited by UHV evaporation on an amorphous substrate, kept at such a temperature as to produce the Ge nanodroplets nucleation in the liquid phase.

A nanocrystalline size dependence of the Raman spectra has been observed and explained in the framework of a phonon confinement model. We have observed the softening of the TO Raman peak predicted by the theory when the dimensions of the particles are decreased. Moreover the observed inhomogeneous broadening of the Raman lines has been correlated with the size distribution of the particles in the samples.

Our results provide a characterization of Ge nanoparticles exhibiting a good crystalline nature, down to about 10 Å, and in conditions of substantial absence of perturbations of the environment.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 452 , 1996 , 249
Copyright
Copyright © Materials Research Society 1997

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References

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