Structural and optical properties of indium tin oxide (ITO) thin films with different compositions prepared by electron beam evaporation

Tin-doped Indium oxide thin films in different compositions (Sn = 0,5,10,15,20 at.wt%) were prepared on glass substrates at the substrate temperature of 250 degrees C in an oxygen atmosphere by electron beam evaporation. The structural and morphological studies were carried out by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The grain size of the ITO films decreased when increasing the dopant concentration of Sn in the In2O3 lattice. Optical properties of the films were studied in the UV-Visible-NIR region (300-1000 nm). The optical energy band gap (E-g), as determined by the dependence of the absorption coefficient on the photon energy at short wavelengths was found to increase from 3.61 to 3.89 eV revealing the ascending loading profile of clopant concentration. Optical Parameters, such as absorption depth, refractive index (n), extinction coefficient (k), packing density, porosity, dispersion energy and single effective oscillator energy were also studied to show the composition dependence of tin-doped indium oxide films. (C) 2009 Elsevier Ltd. All rights reserved.