Influence of Excitation Frequency on Raman Modes of Thin Films

Low energy optical modes of MBE-grown thin films with different values of are investigated using Raman spectroscopy. We also studied the influence of Raman excitation frequency using red and green lasers on scattering intensity of various Raman modes. For those alloys whose bandgap energy is clos...

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Main Authors: A. Dixit, J. S. Thakur, V. M. Naik, R. Naik
Format: Article
Language:English
Published: Wiley 2013-01-01
Series:Advances in Condensed Matter Physics
Online Access:http://dx.doi.org/10.1155/2013/191282
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author A. Dixit
J. S. Thakur
V. M. Naik
R. Naik
author_facet A. Dixit
J. S. Thakur
V. M. Naik
R. Naik
author_sort A. Dixit
collection DOAJ
description Low energy optical modes of MBE-grown thin films with different values of are investigated using Raman spectroscopy. We also studied the influence of Raman excitation frequency using red and green lasers on scattering intensity of various Raman modes. For those alloys whose bandgap energy is close to the red laser, a huge enhancement in the intensities of A1(LO) mode and its 2A1(LO) replica is observed when excited with red laser as compared to the green laser excitation. We found that the energies of longitudinal optical modes (A1(LO) and 2A1(LO)) vary nonlinearly unlike the E2 mode with increasing Ga atomic fraction. A Raman mode ~540 cm−1 was observed in all films with low energy red laser excitation but was absent with green laser excitation. We attribute this mode to A1(TO) mode of the underneath GaN buffer layer.
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spelling doaj-art-a6509059cb4640579932fe32bf87a5f22025-02-03T05:59:07ZengWileyAdvances in Condensed Matter Physics1687-81081687-81242013-01-01201310.1155/2013/191282191282Influence of Excitation Frequency on Raman Modes of Thin FilmsA. Dixit0J. S. Thakur1V. M. Naik2R. Naik3Center in Energy & ICT, Indian Institute of Technology Jodhpur, Rajasthan 342011, IndiaDepartment of Physics and Astronomy, Wayne State University, Detroit, MI 48202, USADepartment of Natural Sciences, University of Michigan-Dearborn, Dearborn, MI 48128, USADepartment of Physics and Astronomy, Wayne State University, Detroit, MI 48202, USALow energy optical modes of MBE-grown thin films with different values of are investigated using Raman spectroscopy. We also studied the influence of Raman excitation frequency using red and green lasers on scattering intensity of various Raman modes. For those alloys whose bandgap energy is close to the red laser, a huge enhancement in the intensities of A1(LO) mode and its 2A1(LO) replica is observed when excited with red laser as compared to the green laser excitation. We found that the energies of longitudinal optical modes (A1(LO) and 2A1(LO)) vary nonlinearly unlike the E2 mode with increasing Ga atomic fraction. A Raman mode ~540 cm−1 was observed in all films with low energy red laser excitation but was absent with green laser excitation. We attribute this mode to A1(TO) mode of the underneath GaN buffer layer.http://dx.doi.org/10.1155/2013/191282
spellingShingle A. Dixit
J. S. Thakur
V. M. Naik
R. Naik
Influence of Excitation Frequency on Raman Modes of Thin Films
Advances in Condensed Matter Physics
title Influence of Excitation Frequency on Raman Modes of Thin Films
title_full Influence of Excitation Frequency on Raman Modes of Thin Films
title_fullStr Influence of Excitation Frequency on Raman Modes of Thin Films
title_full_unstemmed Influence of Excitation Frequency on Raman Modes of Thin Films
title_short Influence of Excitation Frequency on Raman Modes of Thin Films
title_sort influence of excitation frequency on raman modes of thin films
url http://dx.doi.org/10.1155/2013/191282
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AT rnaik influenceofexcitationfrequencyonramanmodesofthinfilms