Figure 3From: The origin of the red emission in n-ZnO nanotubes/p-GaN white light emitting diodes The CIE 1931 x , y chromaticity space of ZnO nanotubes, for (a) as grown, (b) annealed in argon, (c) annealed in air, (d) annealed in oxygen, (e) annealed in nitrogen, and (f) all together.Back to article page