Regular Article

Optical properties of undoped and tin-doped nanostructured In₂O₃ thin films deposited by spray pyrolysis^*

Optoelectronics and Physical Chemistry of Materials Laboratory, Unit Research Associated CNRST-URAC, Ibn Tofail University, Faculty of Sciences, BP 133, Kénitra 14000, Morocco

^a e-mail: fellahinabil@yahoo.fr

Received: 23 July 2015
Revised: 17 November 2015
Accepted: 16 December 2015
Published online: 3 May 2016

Abstract

Tin-doped indium oxide (In₂O₃:Sn) thin films in different concentrations (Sn = 0, 3, 5, 8 at.%) were deposited by reactive chemical pulverisation spray pyrolysis on heated glass substrates at 500 °C. The effect of the tin dopant on the nonlinear optical properties was investigated using X-ray diffraction, transmission, electrical resistivity and third harmonic generation (THG). All films were polycrystalline, and crystallised in a cubic structure with a preferential orientation along the (400) direction. The Sn (5 at.%) doped In₂O₃ thin films exhibited a lower resistivity of 3 × 10^-4 Ω cm, and higher transmission in the visible region of about 94%. Optical parameters, such as the extinction coefficient (k), refractive index (n) and energy band gap (E_g), were also studied to show the composition-dependence of tin-doped indium oxide films. The nonlinear properties of the In₂O₃:Sn thin films have been found to be influenced by doping concentration, and the best value of χ⁽³⁾ = 3 × 10^-11 (esu) was found for the 5 at.% doped sample.