Rapid Synthesis of SnO2 Thin Films using Monoethanolamine through Wet Chemical Route

Abstract

Objectives: To develop a unique wet chemical process for the rapid synthesis of SnO 2 thin films and hence to study the structural, morphological, optical and electrical properties of the films. Methods/Analysis: Polycrystalline SnO 2 thin films having a thickness in the range of 800-1000 nm with crystallite size less than 5 nm were synthesized within a time of 20 minutes and without the need of post-annealing using SILAR technique. Lattice parameters, c/a ratio, cell volume, dislocation density, refractive index, extinction coefficient and porosity of the SnO 2 thin films were determined. Findings: Films have a coarse and porous surface morphology with very fine pores distributed nearly uniformly on the film surface. The crystallite size and strain developed in the SnO 2 films were computed by the Williamson-Hall technique. Microstrain developed in the films is of the order of 10 -3 . SnO 2 films exhibit nearly 70% transmittance in the visible region. The optical band gap of the SnO 2 films is 3.65 eV. The refractive index of the films varies from 2.05 to 2.30 in the 450-1900 nm wavelength range. SnO 2 films exhibit a resistivity in the order of 10 -1 Ωcm. Novelty: Reports a unique rapid wet chemical process for the direct preparation of crystalline SnO 2 thin films using monoethaolamine at a temperature of 80 0 C. Literature survey reveals that no other method has yielded such type of good quality SnO 2 thin films at this temperature and without post annealing or sintering. First time crystalline SnO 2 films were prepared by a wet chemical process within 20 minutes.