Electrical and optical properties of mixed phase Tungsten Trioxide films grown by Laser Pyrolysis

Laser pyrolysis is a synthesis method used to produce thin films and nanomaterials of high quality and purity, by intersecting a laser beam with a chemical precursor. We have chosen laser pyrolysis to synthesize tungsten trioxide starting with tungsten ethoxide precursor. The film had a thickness that varied from 205 nm to 1 µm. X-ray diffraction and Raman spectroscopy confirmed the presence of a mixture of hexagonal and tetragonal phase WO3 in the synthesized film, and it was clear that anneal-ing greatly influenced the phases and types of structures formed. I-V curves of the films showed n-type semicon-ducting behaviour, but the mixed phase appeared to cause a similar behaviour of dopants in a semiconductor. The refractive index decreased with increasing wavelength and gave values of up to 21 at low wavelengths. The av