GaN epitaxial layers on inhomogeneous buffer layer: electrical and optical propertiesC. Grazzi, A. Castaldini, A. Cavallini, H. P. D. Schenk, P. Gibart and H. P. StrunkEur. Phys. J. Appl. Phys., 27 1-3 (2004) 193-195DOI: https://doi.org/10.1051/epjap:2004117