Femtosecond excitation of radial breathing mode in 2-D arrayed GaN nanorods

Hung Pin Chen, Yueh Chun Wu, Pierre Adrien Mante, Shang Ju Tu, Jinn Kong Sheu, Chi Kuang Sun

Research output: Journal article publicationJournal articleAcademic researchpeer-review

16 Citations (Scopus)


Radial breathing oscillation of 2-D arrayed GaN nanorods was successfully excited in rods with different diameters by using femtosecond transient reflectivity measurement. Through analyzing thus measured diameter dependent oscillation frequency, we discovered that modification of the mechanical property appeared in the 2-D arrayed piezoelectric GaN nanorods, fabricated on top of a bulk substrate, when the rod diameter was on the order of or less than 50 nm. Our measurement observed a much reduced elastic stiffness constant (C11) of 193 ± 24 GPa in 35nm diameter nanorods, compared with the 365 ± 2 GPa in bulk GaN. This size-reduction induced mechanical modification would be a critical factor to be considered for future sensing and energy applications. Our study also provides a new spectroscopic method to explore the size-reduction-induced softening effect through the measurement of the radial breathing oscillations.

Original languageEnglish
Pages (from-to)16611-16617
Number of pages7
JournalOptics Express
Issue number15
Publication statusPublished - 16 Jul 2012
Externally publishedYes

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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