Raman scattering as a probe of phonon confinement and surface optical modes in semiconducting nanowires

Adu, Kofi W.; Xiong, Qihua; Gutiérrez, Humberto; Chen, G.; Eklund, P. C.

doi:10.1007/s00339-006-3716-8

Cited by 145 publications

(174 citation statements)

References 88 publications

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“…It has been showed that the shape (diameter 29 and cross section 30 ) of the nanowire, the surrounding medium, 31 and the defect density 32 of the nanowire influences the SO mode. Thus, the SO mode shifts to lower wave numbers when decreasing the diameter of the nanowire.…”

Section: Surface Optical Phonon In Inas Nanowiresmentioning

confidence: 99%

Polarized and resonant Raman spectroscopy on single InAs nanowires

et al. 2011

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We report polarized Raman scattering and resonant Raman scattering studies on single InAs nanowires. Polarized Raman experiments show that the highest scattering intensity is obtained when both the incident and analyzed light polarizations are perpendicular to the nanowire axis. InAs wurtzite optical modes are observed. The obtained wurtzite modes are consistent with the selection rules and also with the results of calculations using an extended rigid-ion model. Additional resonant Raman scattering experiments reveal a redshifted E 1 transition for InAs nanowires compared to the bulk zinc-blende InAs transition due to the dominance of the wurtzite phase in the nanowires. Ab initio calculations of the electronic band structure for wurtzite and zinc-blende InAs phases corroborate the observed values for the E 1 transitions.

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Section: Surface Optical Phonon In Inas Nanowiresmentioning

confidence: 99%

Polarized and resonant Raman spectroscopy on single InAs nanowires

et al. 2011

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“…[29][30][31] Additionally, modes such as the ones associated with surface phonons have been detected. [32][33][34][35] In this work, scanning Raman spectroscopy is performed on GaAs nanowires with zinc-blende and wurtzite structures. The paper is structured as follows: after presenting theoretical considerations on the phonon dispersion and selection rules for both structures in Sec.…”

Section: Introductionmentioning

confidence: 99%

Raman spectroscopy of wurtzite and zinc-blende GaAs nanowires: Polarization dependence, selection rules, and strain effects

et al. 2009

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Polarization-dependent Raman scattering experiments realized on single GaAs nanowires with different percentages of zinc-blende and wurtzite structure are presented. The selection rules for the special case of nanowires are found and discussed. In the case of zinc-blende, the transversal optical mode E 1 ͑TO͒ at 267 cm −1 exhibits the highest intensity when the incident and analyzed polarization are parallel to the nanowire axis. This is a consequence of the nanowire geometry and dielectric mismatch with the environment, and in quite good agreement with the Raman selection rules. We also find a consistent splitting of 1 cm −1 of the E 1 ͑TO͒. The transversal optical mode related to the wurtzite structure, E 2 H , is measured between 254 and 256 cm −1 , depending on the wurtzite content. The azimuthal dependence of E 2 H indicates that the mode is excited with the highest efficiency when the incident and analyzed polarization are perpendicular to the nanowire axis, in agreement with the selection rules. The presence of strain between wurtzite and zinc-blende is analyzed by the relative shift of the E 1 ͑TO͒ and E 2 H modes. Finally, the influence of the surface roughness in the intensity of the longitudinal optical mode on ͕110͖ facets is presented.

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“…There are two characteristics which are distinctive of the SO modes and can therefore allow a reliable assignment of the mode: the dependence of the position (1) on the dielectric constant of the medium surrounding the wires and (2) on the diameter (or on the period of the diameter oscillation) of the wires. Indeed, it has already been shown that the SO mode position down shift increasing the dielectric constant of the surrounding optical medium and decreasing the nanowire diameter (Shan et al, 2006;Adu et al, 2006a;Spirkoska et al, 2008). Furthermore, the frequency of the SO modes at the center of the Brillouin zone is located between those of the TO and the LO.…”

Section: Appearance Of New Modes: Surface and Breathing Modesmentioning

confidence: 96%

“…More details on the experiments can be found elsewhere (Spirkoska et al, 2008). Indeed, it has been proved that the cross section of the nanowires influences the surface mode dispersion (Adu et al, 2006a;Xiong et al, 2006). In these works, a model for nanowire with rectangular cross section has been developed.…”

Section: Appearance Of New Modes: Surface and Breathing Modesmentioning

confidence: 99%