Facile synthesis and an effective doping method for ZnO:In3+ nanorods with improved optical properties

The sol-gel spin-coating method is usually used for thin-film deposition rather than to grow one-dimensional nanostructures. In this study, a novel regrowth method for spin-coated ZnO:In3+ films is demonstrated, using vapor-confined face-to-face annealing (VC-FTFA) in which a mica sheet is inserted between the two films prior to FTFA. ZnO:In3+ nanorods are regrown when indium chloride is used as the solvent because ZnCl2 and InCl3 vapors are generated and confined between the films. The near-band-edge emission intensity of the ZnO:In3+ nanorods resulting from VC-FTFA at 700 °C is enhanced by a factor of 17 compared with that of ZnO:In3+ films annealed in open air at the same temperature. Our method offers a simple and low-cost route for the fabrication of ZnO nanorods.