Structural and optical properties of indium oxide thin films prepared by an ultrasonic spray CVD process

Polycrystalline In2O3 thin films have been synthesized by a modified chemical vapor deposition process using the pyrolysis of an aerosol generated by ultrahigh frequency spraying of a volatile precursor solution. The deposition has been carried out on glass substrates (350–550 °C). X-Ray diffraction has shown that deposited films are polycrystalline without second phases. The morphology of the surface as function of the substrate temperature has been studied using scanning electron microscopy (LEO Stereoscan 440). Transmission and reflection spectra of the sprayed films were examined in the 260–2600 nm spectral range and, for investigated films, the transmission coefficient in the visible and infrared regions exceed 85% and is weakly affected by deposition temperature. The optical band gap values, Eg, ranged between 3.57 and 3.68 eV. The Urbach tail parameter E0, was calculated for films deposited at different temperatures.