Effect of Composition and Annealing on Structural and Optical Properties of (ZnO)_1-X (TiO_2)_X Thin Films Prepared by Sol-Gel Method

The study describes effect of composition parameter, x, and annealing-temperature, ta , on structural, and optical properties of (zno)_1-x(tio_2)_x thin-films prepared by sol-gel method. experimental results are explained and theoretical equations are suggested for optical energy-gap, eg, and urbach-energy, eu in terms of their variation with (x) and (ta). with increased x and ta, eg decreases whereas eu increases. the behavior of eg was explained by evoking that increasing x will randomize the crystal periodicity, and that annealing temperature (400, 500, and 600) ⁰c relaxes the structure more towards better crystalline forms. the increase of eu with increased x was attributed to the lower mass of ti ions as compared to that of zn ions. generally, making composites destroys the crystalinity observed in pure zno and pure tio_2 films but annealing does improve the quality of the film in terms of its degree of crystal structure.