Comparison of spray pyrolyzed FTO, ATO and ITO coatings for flat and bent glass substrates

• Published in: Thin solid films 1999-08, Vol.351 (1-2), p.109-114
• Main Authors: BISHT, H, EUN, H.-T, MEHRTENS, A, AEGERTER, M. A
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Electrical properties of specific thin films; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of specific thin films; Other inorganic semiconductors; Other semiconductors; Physics; Spray coating techniques
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/s0040-6090(99)00254-0

Transparent conductive FTO, ATO and ITO films were synthesized by spray pyrolysis technique on flat 12 x 12 cm borosilicate glass substrates at 500-550 degree C and investigated with respect to their electrical and optical properties. The resistivity of sprayed ITO films decreases with the thickness down to 3.0 x 10 super(-4) Omega cm (300 nm). The optical transmission in the visible range is 80% and the near IR reflection up to 96% for thicknesses larger than 300 nm. A reducing treatment at 400 degree C in forming gas still decreases the resistivity by a factor of two. Bending of the coated glasses in air at 650 degree C for 1.5 h increases the resistivity of the coatings on the tensile side of the substrate by a factor of 3-4 and by a factor 2 on the compressed side. A subsequent reducing treatment in forming gas at 400 degree C leads to a drastic decrease of resistivity in both cases by a factor of 5-7 with resulting value rho identical with 2-3 x 10 super(-4) Omega cm. ATO layers have lower visible transmission (70-75%) due to stronger absorption and a higher resistivity ( rho identical with 1 x 10 super(-3) Omega cm). Spray pyrolyzed FTO coatings have a resistivity rho identical with 5 x 10 super(-3) Omega cm for film thicknesses > 350 nm.