Effect of N isotopic mass on the photoluminescence and cathodoluminescence spectra of gallium nitride F. J. Manjón, M. A. Hernández-Fenollosa, B. Marí, S. F. Li, C. D. Poweleit, A. Bell, J. Menéndez and M. Cardona Eur. Phys. J. B, 40 4 (2004) 453-458 Published online: 20 July 2004 DOI: 10.1140/epjb/e2004-00211-1