Transparent and conductive W-doped SnO2 thin films fabricated by an aqueous solution process

• Published in: Thin solid films 2013-10, Vol.544, p.419-426
• Main Authors: Wang, Mi, Gao, Yanfeng, Chen, Zhang, Cao, Chuanxiang, Zhou, Jiadong, Dai, Lei, Guo, Xuhong
• Format: Article
• Language: English
• Subjects: Composition and phase identification; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Growth from solutions; Materials science; Methods of crystal growth; physics of crystal growth; Methods of nanofabrication; Physics; Spin-coating; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film; Thin film structure and morphology; Transparent conductive oxide; Tungsten-doped tin oxide
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2013.02.088

High-quality transparent and conductive tungsten-doped tin oxide (SnO2:W) thin films with different thickness (from 60 to 600±10nm) were fabricated on quartz glass substrates by a solution-based method. A stable solution was prepared from tin chloride and ammonium tungstate together with polyvinyl alcohol as a film-forming promoter. It was found that all films showed homogeneous composition, smooth surface with no cracks and high transparency with the optical band gap ranging from 3.93 to 4.31eV. The effect of tungsten concentration, spin rate and annealing temperature on the morphological, electrical and optical properties of the films has been investigated. W doping has a large influence on the microstructure and the conductivity of the SnO2 thin films. The lowest resistivity of 2.8×10−3 Ω·cm was obtained for a SnO2: 3 at% W film, which was prepared at 3000rpm and annealed at 800°C in air. An eight-layer film with a sheet resistance of 60 Ω/□ and a thickness of 606nm could be fabricated by multiple coating operation, which still exhibited an optical transmittance of over 80% in the visible region from 400 to 700nm. •Transparent conductive SnO2:W thin films were fabricated by a solution-based method.•A small addition of W effectively lowered the resistivity of SnO2 films.•The lowest resistivity of 2.8×10−3 Ω·cm was obtained for a SnO2: 3 at% W film.•These films exhibit an optical transmittance of over 80% in the visible region.•These films show the optical band gap ranging from 3.93 to 4.31eV.