Characterizations of strain and defect free GaN nanorods on Si(111)   substrates
  GaN-nanorods grown on Si(111) substrates are found strain- and defect-free as characterized by micro Raman spectroscopy, secondary electron (SE) and cathode-luminescence (CL) imaging. The matrix supporting the nanorods bears the brunt of all strains, strain-relaxations, and defect generations, giving the nanorods an ideal environment to grow to perfection. Photo-excitations by the Raman laser source and electron irradiation during CL imaging lead to an increase of non-equilibrium electrons, suggesting an effective approach to photo-emitting or field emitting device applications. The nanorods, largely isolated from but perfectly aligned with the sustaining matrix, are grown in excellent epitaxy with the Si substrates. 
H. W. Seo, Q. Y. Chen, M. N. Iliev, W. K. Chu, L. W. Tu, C. L. Hsiao,   and James K. Meen