Atomistic Origin of the Thermally Driven Softening of Raman Optical Phonons in Group III Nitrides
| Autor: | Beng Kang Tay, T. C. Au Yeung, Chang Q. Sun, Mingxia Gu, Likun Pan |
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| Rok vydání: | 2007 |
| Předmět: |
Materials science
Condensed matter physics Phonon Bond strength Coordination number Nitride Thermal expansion Surfaces Coatings and Films Electronic Optical and Magnetic Materials Bond length Vibration Condensed Matter::Materials Science symbols.namesake General Energy Computational chemistry symbols Physical and Theoretical Chemistry Raman spectroscopy |
| Zdroj: | The Journal of Physical Chemistry C. 111:13606-13610 |
| ISSN: | 1932-7455 1932-7447 |
| DOI: | 10.1021/jp0727087 |
| Popis: | It has long been puzzling regarding the physical origin of the thermally induced red-shift of Raman optical phonons in group III nitride crystals despite some possible mechanisms such as phonon decay, thermal expansion, interfacial effects, or their combinations. Here we show that an extension of the recent approach [Sun, C. Q.; Pan, L. K.; Li, C. M.; Li, S. Phys. Rev. B 2005, 72, 134301] to the functional dependence of the frequency of Raman optical modes on the atomic bonding identities (bond length, bond strength, and atomic coordination numbers) to the temperature domain has enabled us to gain a simple solution with improved understanding of the thermally induced red-shift of Raman optical phonons. Reproduction of the measured temperature dependence of the Raman shift of AlN, GaN, and InN reveals that the thermally driven red-shift arises simply from bond vibration and bond expansion, together with derived information about the mode cohesive energy. |
| Databáze: | OpenAIRE |
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