Growth, structural, electrical and optical properties of the thermally evaporated tungsten trioxide (WO 3) thin films

• Published in: Materials chemistry and physics Vol. 114; no. 1; pp. 475 - 478
• Main Authors: Patel, K.J., Panchal, C.J., Kheraj, V.A., Desai, M.S.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-03-2009
• Subjects: Electrical properties; Optical properties; Tungsten trioxide thin film; Electrical properties; Tungsten trioxide thin film; Optical properties
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/j.matchemphys.2008.09.071

Tungsten trioxide (WO
3) thin films are of great interest due to their enormous and promising applications in various opto-electronic thin-film devices. We have investigated the structural, electrical, and optical properties of the WO
3 thin films grown by thermal evaporation of WO
3 powder and their dependence on growth condition. The WO
3 thin films were grown on glass substrates at different substrate temperature varying from room temperature to 510
°C. The structural characterization and surface morphology were carried out using X-ray diffraction and atomic force microscopy, respectively. The amorphous films were obtained at substrate temperatures below 450
°C whereas films grown above 450
°C were crystalline. The surface roughness and the grain size of the films increase on increasing the substrate temperature. The electrical characterization has been carried out using four-point-probe methods. The resistivity of the films decreases significantly while the carrier concentration and mobility increase with the substrate temperature. The transparency and optical energy band-gap,
E
g, of the films are found to decrease monotonically as the substrate temperature increases.