Raman scattering in GaN pillar arrays

We present a detailed study of GaN pillar arrays by atomic force microscopy (AFM), Raman spectroscopy, and photoluminescence (PL) spectroscopy. AFM is used to characterize the shape of the GaN pillars and revealed a large roughness of etched pillar surfaces. Raman scattering spectra of the pillars are well described by angular dispersion of polar optical phonons induced by the three-dimensional shape of the pillar. Additional Raman scattering has been tentatively assigned to the activation of the high frequency B-1 silent mode by defects introduced during the ion etching. This result is well correlated with the appearance of donor and acceptor-related PL of the GaN pillars. N vacancy or/and Ga interstitials would be likely candidates for donors in the nonstoichiometric GaN near the surface of the etched pillars. (C) 2002 American Institute of Physics.


Published in:
Journal of Applied Physics, 91, 5, 2866-2869
Year:
2002
ISSN:
0021-8979
Keywords:
Laboratories:




 Record created 2010-10-05, last modified 2018-03-17


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