Tunable visible emission in nanostructured thin films and bulk ZnO

This paper offers new insights into the physical phenomena in light emission from ZnO. The effect of the annealing atmosphere and temperature on defect-related emission in ZnO thin films prepared by the sol–gel method and nonpolar ZnO bulk substrates is investigated by photoluminescence spectroscopy, transmission electron microscopy, and DC electrical measurements. It is demonstrated that the post-annealing treatment is a powerful tool to modify intrinsic/extrinsic defects in ZnO and that the defect-related emission can be accurately tailored in a wide range from blue to red by changing the post-deposition processing parameters. Accurate tailoring of the deep-level emission wavelength in ZnO is of great importance in optoelectronics, particularly in white-light-emitting diodes, display devices, or biological labeling. Graphical abstract