The interface optical phonon and electron-phonon interaction in GaN/AlN spherical heterostructures W. D. Huang, Y. J. Ren, S. Y. Wei and J. H. Wang Eur. Phys. J. Appl. Phys., 43 1 (2008) 73-77 Published online: 19 June 2008 DOI: 10.1051/epjap:2008127