Abstract
Transparent polycrystalline tin oxide (SnO2) thin films were deposited on commercial microscope glass substrates using
spray pyrolysis method. Thin films were deposited at various nozzle-to-substrate distances from 20 to 40 cm in steps of 5
cm and at various substrate temperatures ranging between 380 to 440 °C in steps of 20 °C. The thin films are found to have
a tetragonal rutile structure. Lattice parameters were calculated as a = 4.74 Å and c = 3.18 Å. The surface morphology of
the films were imaged by SEM (Scanning Electron Microscope). The average grain size of the films obtained were 22.3-
74.8 nm by using Scherrer’s formula. The films were found to exhibit high transmittance >90 % in the visible regions.
Absorption coefficient α and the thickness of the film t were calculated from interference of transmittance spectra. Refractive
index n and extinction coefficient k were determined from transmittance spectrum in the ultraviolet-visible-near infrared
regions using envelope methods. The refractive index is found to vary between 1.76-1.92 in the wavelength range of 400-
1100 nm. The values direct band gaps of the films obtained were 3.99-4.11 eV. The electrical resistivity (ρ) of the films
obtained were (2.47-7.13)⋅10−4 Ωcm by using Ohm’s law..
Keywords
Tin oxide, Spray pyrolysis method, Thin films, Refractive index.
Citation
E. GÜNERI, C. GÜMÜŞ, F. MANSUR, F. KIRMIZIGÜL, Studies on properties of sprayed SnO2 thin films as a function of substrate-nozzle distance and substrate temperature, Optoelectronics and Advanced Materials - Rapid Communications, 3, 4, April 2009, pp.383-389 (2009).
Submitted at: April 9, 2009
Accepted at: April 23, 2009