Applied Surface Science, Vol.355, 242-249, 2015
Effect of temperature and NO2 surface adsorption on electrical properties of screen printed ITO thin film
Indium tin oxide films with thicknesses of about 1 pm were prepared using the screen printing technique. Preliminary X-ray diffraction studies show that the formed ITO crystallizes in the cubic crystal system. The crystallite size (D) and the microstrain (epsilon(str)) were investigated using Scherrer formula and Williamson-Hall analysis. Scanning electron microscopy and transmission electron microscopy show that the ITO films are granular, essentially composed of uniformly distributed sub-spherical like grains. The variation of the DC conductivity with temperature confirms the presence of three activation energies, indicating the presence of different scattering mechanisms essentially dominated by oxygen adsorption and thermal excitation of electrons in the conduction band. Detailed studies of the dielectric parameters (i.e., epsilon* and tan delta) of the compound as a function of temperature and NO2 adsorption (at various range of frequencies) reveal that their values are strongly dependent on temperature and NO2 adsorption. (C) 2015 Elsevier B.V. All rights reserved.