Raman spectroscopy of nanocrystalline GaN synthesized by arc plasma

Autor:	Guangtian Zou, Yanfa Yan, X. H. Wu, Haibin Yang, Y. Y. Yang, Shanqing Zhang, Huan Li, K. T. Yue
Rok vydání:	2002
Předmět:	Materials science Phonon Band gap Analytical chemistry General Physics and Astronomy Molecular physics Nanocrystalline material symbols.namesake X-ray Raman scattering symbols Coherent anti-Stokes Raman spectroscopy Raman spectroscopy Raman scattering Wurtzite crystal structure
Zdroj:	Journal of Applied Physics. 91:4562-4567
ISSN:	1089-7550 0021-8979
DOI:	10.1063/1.1452762
Popis:	We report on a Raman study of nanocrystalline GaN with the wurtzite structure synthesized by arc plasma method. Resonant Raman scattering is observed using 514.5 nm (2.41 eV) laser excitation, which is near the band gap of the “yellow band” (2.2–2.3 eV). Under such near-resonant excitation, new Raman bands unexpected in an ideal wurtzite GaN crystal were found. The transverse optical modes of A1 (531 cm−1) and E1 (560 cm−1), and the nonpolar modes of E2 [567 cm−1 (high) and 143 cm−1 (low)] normally observed in bulk crystals, were recorded and were observed to be resonantly enhanced. Two new bands (680 and 344 cm−1) were assigned to the inactive optical phonon modes B1 (high) and B1 (low), respectively. A broadband centered at 710 cm−1 was attributed to surface modes of the nanocrystals, providing good agreement with the calculated result based on Frohlich theory. As a result of this study, Raman scattering of GaN nanocrystals has been characterized.
Databáze:	OpenAIRE
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