Surface phonons in GaAs cylinders

Abstract

Raman scattering from arrays of GaAs quantum cylinders with radii down to 30 nm has been observed. The spectra show an enhanced TO phonon intensity due to a change in the first-order selection rules. In addition, the smallest cylinders exhibit an extra spectral feature between the TO and LO phonons. The behaviour of this additional peak as a function of the scattering geometry, the cylinder size and the variation of the medium surrounding the cylinders is consistent with a theoretical model of the surface phonons of a cylinder.

Self-Assembled InAs(N) Quantum Dots Grown by Molecular Beam Epitaxy on GaAs (100)*

“…They are solutions to Maxwell's equations with appropriate boundary conditions [B. E. Sernelius, 2001]. Many authors have studied theoretically the SO-modes from different geometries (cylindr ical and spheroids shape) in nanoparticles, nanowires and QDs, by using the approximation of a dielectric continuum and modeling of valence-force fields to explain the connection between SO phonon modes and the geometrical shape of a semiconductor QD [] [Watt M et al, 1990;-37, Gupta R et al, 2203 -38]. In our samples we observed that the integrated Raman intensity, and the position of the SOmode for the samples M3 -M4 is clearly dependent of the volume and facets formed on SADQs.…”

Phonon Confinement Effect in III-V Nanowires

“…This model was successfully applied to describe the SO phonon spectra of microcrystalline spheres [44], GaAs NWs [47], Si NWs [48], and GaAs cylinders [50].…”

Optical Phonon Modes and Electron-optical Phonon Interaction in Core-shell Semiconductor Quantum Wires

“…In the past, several workers [10][11][12][13][14][15] had carried out studies of the electron interaction with longitudinal optical (LO) phonons in quantum wires considering the modification of the electron energy spectrum and wave function due to their space localization but assuming the bulk forms for LO phonon modes. However, it was shown that the reduced sized scale and dimensionality have great influence leading to phonon confinement and changes in phonon modes [16][17][18][19]. These changes become an essential part of the description of electron-phonon interaction and affect strongly the transport properties of electrons in quantum wires.…”