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Your search keyword '"Artús, Lluís"' showing total 2 results
Start Over Author "Artús, Lluís" Publisher john wiley & sons
2 results on '"Artús, Lluís"'

1. Raman scattering by folded acoustic phonons in InGaN/GaN superlattices

Author

Ibáñez Insa, Jordi, Rapaport, A., Boney, C., Oliva, Ramón, Cuscó, Ramón, Bensaoula, A., and Artús, Lluís

Subjects
Raman scattering, Superlattices, Folded acoustic phonons
Abstract

We use Raman scattering to investigate the folded longitudinal acoustic (LA) phonons in a series of In xGa 1-xN/GaN superlattices (SLs) grown by molecular beam epitaxy with different compositions (15% < x < 38%) and SL periods (from 8 to 20 nm). A novel, ultralow wavenumber filtering module, which provides access to ultralow wavenumber Raman modes on single-grating spectrometers, has been used to perform the Raman measurements. Zone-folding effects are observed, and the wavenumber behavior of the folded LA modes is well reproduced with a linear dispersion for the folded LA modes as predicted by elastic continuum theory. We employ the wavenumber of the doublets to evaluate the period of the SLs. Copyright © 2011 John Wiley & Sons, Ltd., Financial support from the Spanish Ministry and Innovation (Project MAT2010-16116) and from CSIC (PIE 2009) is acknowl- edged.

Published
2012

2. Ultraviolet Raman scattering in ZnO nanowires: Quasimode mixing and temperature effects

Author

Alarcón-Lladó, Esther, Ibáñez Insa, Jordi, Cuscó, Ramón, Artús, Lluís, Prades, J. Daniel, Estradé, S., Morante, Joan Ramón, Alarcón-Lladó, Esther, Ibáñez Insa, Jordi, Cuscó, Ramón, Artús, Lluís, Prades, J. Daniel, Estradé, S., and Morante, Joan Ramón

Abstract

We use near-resonance Raman scattering to investigate zinc oxide (ZnO) nanowires grown by chemical vapor deposition on Si substrates. We discuss the role of quasimode mixing on the wavenumber of the longitudinal optical (LO) bands, and we perform Raman measurements with different excitation powers to investigate possible laser heating effects. We find that in the Raman spectra of as-deposited nanowires grown along the c-axis of wurtzite, the LO bands are located slightly below the E1(LO) mode of bulk ZnO. We perform a calculation of the expected LO wavenumber in an ensemble of randomly oriented nanowires. Our analysis shows that light refraction, together with the orientation-dependent cross-section of the nanowires for the incoming light, counterbalances quasimode mixing effects in the as-grown product, giving rise to LO bands that are barely redshifted relative to the E1(LO) mode. In the case of ZnO nanowires that have been mechanically removed (scratched) and subsequently deposited onto separate Si substrates, we observe clear laser-induced heating. Temperature effects account well for the Raman wavenumber shifts displayed by the LO bands in the Raman spectra of the scratched nanowires. Copyright © 2010 John Wiley & Sons, Ltd.

Published
2011

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