Hydrothermal synthesis of Al-doped ZnO nanorod arrays on Si substrate

High-density, single-crystal, quasi-aligned, Al-doped ZnO nanorod arrays were grown on a silicon substrate using a low temperature hydrothermal process. Different Al atomic concentrations have been successfully doped into the ZnO lattice using different Zn and Al precursors in the synthesis solution. The effects of Al doping on the microstructure characteristics, elemental composition and optical properties of the nanorod arrays were studied. It has been shown that the morphology, density, and surface compositions of ZnO nanorod arrays are sensitive to the concentration and variety of zinc and aluminum precursors. The ratio of ultraviolet to visible emission peak (I_UV/I_Vis) increases as the aluminum nitrate concentration increases up to 5 mM. The best optical property was obtained for Al-doped ZnO nanorods grown in a 0.04 M zinc acetate dihydrate solution with 5 mM of aluminum sulfate hydrate. The improved optical property in Al-doped ZnO nanorods can be attributed to the decrease in oxygen deficiency after Al doping.