We present a Raman study of the phonon spectra of periodical structures with (In,Ga)As QDs in (Al,Ga)As matrix as well as AlAs QDs embedded in InAs.

The nanostructures studied were grown by molecular beam epitaxy in the Stranski-Krastanov growth mode on (001)-oriented GaAs substrates.

Low frequency resonant Raman scattering by acoustic phonons was observed in the QD structures. The periodic oscillations seen in the Raman spectra are well described by the elastic continuum model.

Raman scattering by confined TO and LO phonons was observed in both in InAs and AlAs QDs. Optical phonons of QDs are strongly affected by both strain and confinement. The Raman study reveals a two-mode behavior of optical phonons in the whole composition range for both InGaAs QDs and the AlGaAs matrix.

With increasing excitation energy (from 1.8 to 2.4 eV) a red shift of InAs and GaAs-like LO phonons in InGaAs QDs is observed which is explained by selective resonant Raman scattering.

Interface InAs- and GaAs-like phonons as well as AlAs- and GaAs-like phonons were observed in InGaAs QDs and the AlGaAs matrix, respectively. Their frequency positions were analyzed as a function of the alloy content within the dielectric continuum model. The positions of IF phonons in the QD structures observed in the experiment agree well with calculated ones assuming the QDs have a shape of oblate ellipsoids.

In the vicinity with E₀ resonance in QDs, up to third-order scattering is observed, involving both pure overtones of the first-order InAs, GaAs and AlAs optical and interface phonons and combination of phonons from the materials. Possible mechanisms of these processes are discussed.

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/16108 must be provided.

1. Raman scattering on semiconductor microtubes
2. Probing the structure of core-shell nanoparticles by resonant Raman scattering spectroscopy
3. Resonant Raman spectroscopy of confined and surface phonons in CdSe-caped CdS nanoparticles
4. Phonon spectra of quaternary II-VI semiconductor nanocrystals grown in glass matrices
5. Surface phonons in CdS_1–xSe_x semiconductor nanoparticles embedded in dielectric media
6. Phonon spectroscopy of CdSe_1–xTe_x nanocrystals grown in a borosilicate glass
7. Raman Monitoring of Organic/Inorganic Interface Formation
8. Negative magnetoresistance of a high-mobility 2D electron gas in a GaAs quantum well with AlAs/GaAs superlattice barriers in a nonlinear regime
9. Formation of Ge nanoislands on pure and oxidized Si surface by MBE