Photoluminescence behavior of purpose-built ZnO arrays on different growth substrates

We fabricated purpose-built ZnO arrays directly on ITO conductive glass and in nanochannels of polycarbonate membrane, and investigated their photoluminescence properties. The former sample exhibited only two peaks at 360 and 390 nm, which correspond to the recombination of e–h⁺, and UV band emission, which confirms minimal defects existed. After annealing, the second kind of samples showed an additional two peaks, located at 488 and 540 nm. This fact may be explained by the defects in the newly formed ZnO, which is derived from Zn²⁺ adsorbed on the surface of the ZnO nanoparticles in the nanochannel.