Hydrothermal Growth and Properties of Rod-like ZnO Submicron Crystals on Al-doped ZnO Seed Layers with Different Al Concentrations

The authors used a sol-gel method to deposit Al-doped ZnO (AZO) thin films on Si substrates and a hydrothermal method to grow ZnO crystals on the as-prepared AZO seed layers. Though the crystallinity of the seed layers was enhanced by Al doping, for Al doping up to 3 at.%, the full width at half maximum (FWHM) of the ZnO (002) diffraction peak increased, resulting in a decrease in the average grain size. The intensity of the ZnO (002) diffraction peak of ZnO crystals grown on AZO seed layers increased as the Al doping concentration was increased to 1.0 at.%. The narrowest FWHM in the photoluminescence spectrum, 132 meV was obtained at an Al doping concentration of 1.0 at.%. These results indicate that the structural and the optical properties of ZnO crystals grown on seed layers can be enhanced by introducing a small amount of an Al dopant into the seed layers.