Figure 4From: The fabrication of white light-emitting diodes using the n-ZnO/NiO/p-GaN heterojunction with enhanced luminescenceComparative CL spectra of ZnO nanorods and nanotubes with and without buffer layer. (a) CL spectra of ZnO nanorods (b) CL spectra of ZnO nanotubes.Back to article page