Tungsten oxide thin films were deposited on glass substrates by the magnetron sputtering of WO3 bulk at room temperature. The deposited films were annealed at different temperatures in air. The structural measurements...Tungsten oxide thin films were deposited on glass substrates by the magnetron sputtering of WO3 bulk at room temperature. The deposited films were annealed at different temperatures in air. The structural measurements indicate that the films annealed below 300℃ were amorphous, while the films annealed at 400 ℃ were mixed crystalline with hexagonal and triclinic phases of WO3. It was observed that the crystallization of the annealed films becomes more and more distinct with an increase in the annealing temperature. At 400 ℃, nanorod-like structures were observed on the film surface when the annealing time was increased from 60 min to 180 min. The presence of W=O stretching, W-O-W stretching, W-O-W bending and various lattice vibration modes were observed in Raman measurements. The optical absorption behaviors of the films in the range of 450-800 nm are very different with changing annealing temperatures from the room temperature to 400 ℃. After annealing at 400 ℃, the film becomes almost transparent. Increasing annealing time at 400 ℃ can lead to a small blue shift of the optical gap of the film.展开更多
Thin films produced by electrostatic spray deposition （ESD） have nanometer-sized structures despite the initial sprayed droplets being typically a few tens of microns in diameter. The size and morphology of the resu...Thin films produced by electrostatic spray deposition （ESD） have nanometer-sized structures despite the initial sprayed droplets being typically a few tens of microns in diameter. The size and morphology of the resulting structures is not only affected by the solvent properties and drying kinetics, hut also by Coulomb fission owing to the high surface charge density that the droplets build up upon evaporation. In this work we modulate the charge density of the droplets by inducing ionic wind along the spray, and produce mesoscopic structures. Using WO3 as an example, we show that the technique provides a practical way to control the morphology of thin films produced by ESD.展开更多
基金supported by the Young Scientists Fund of the National Natural Science Foundation of China(Grant Nos.11104365 and 11104366)the Hubei Key Laboratory of Low Dimensional Optoelectronic Material and Devices,China(Grant No.13XKL02002)
文摘Tungsten oxide thin films were deposited on glass substrates by the magnetron sputtering of WO3 bulk at room temperature. The deposited films were annealed at different temperatures in air. The structural measurements indicate that the films annealed below 300℃ were amorphous, while the films annealed at 400 ℃ were mixed crystalline with hexagonal and triclinic phases of WO3. It was observed that the crystallization of the annealed films becomes more and more distinct with an increase in the annealing temperature. At 400 ℃, nanorod-like structures were observed on the film surface when the annealing time was increased from 60 min to 180 min. The presence of W=O stretching, W-O-W stretching, W-O-W bending and various lattice vibration modes were observed in Raman measurements. The optical absorption behaviors of the films in the range of 450-800 nm are very different with changing annealing temperatures from the room temperature to 400 ℃. After annealing at 400 ℃, the film becomes almost transparent. Increasing annealing time at 400 ℃ can lead to a small blue shift of the optical gap of the film.
文摘Thin films produced by electrostatic spray deposition （ESD） have nanometer-sized structures despite the initial sprayed droplets being typically a few tens of microns in diameter. The size and morphology of the resulting structures is not only affected by the solvent properties and drying kinetics, hut also by Coulomb fission owing to the high surface charge density that the droplets build up upon evaporation. In this work we modulate the charge density of the droplets by inducing ionic wind along the spray, and produce mesoscopic structures. Using WO3 as an example, we show that the technique provides a practical way to control the morphology of thin films produced by ESD.
