Structure and optical properties of Mn2+ ions doped ZnO/Zn2SiO4 composite thin films

ZnO/Zn2SiO4 nanocomposite thin films doped with 1 mol% of Mn2+ ions were successfully synthesized by sol-gel spin coating method and subsequent thermal annealing in the ranges of 500-1000 degrees C. Effects of ZnO and SiO2 molar ratio and annealing conditions, including one or two-step annealing, on the microstructure and PL properties of these thin films were investigated using X-ray diffraction, high-resolution transmission electron microscopy, UV-visible absorption spectroscopy, and emission spectroscopy. Results showed that precipitation of ZnO nanocrystals and willemite nanocrystals can be tailored by the composition and annealing conditions. Two-step annealing lead to more versatile modulation of the microstructure and dual band emission with blue from ZnO nanocrystals and green emission from Mn2+-doped Zn2SiO4 nanocrystals were achieved simultaneously, making these composite thin film materials promising for various optoelectronic applications. (C) 2019 Elsevier B.V. All rights reserved.