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.

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

Effect of substrate temperature on structural, optical and electrical properties of pulsed laser ablated nanostructured indium oxide films

Indium oxide (InOx) films with a thickness of 10–1100 nm were deposited onto Corning 7059 glass and silica substrates at various substrate temperatures. An unusual decrease of the lateral grain size with increasing substrate temperature during deposition was found. The changes in the conductivity of the films after exposure to ultraviolet light in vacuum and subsequent oxidation in ozone atmosphere were analyzed and related to their structural and morphological properties. It is suggested that the photoreduction and oxidation treatments affect only a thin layer less than 10 nm at the surface of the film, while the minimum bulk conductivity is mainly determined by the structural and morphological properties.

Dependence of the photoreduction and oxidation behavior of indium oxide films on substrate temperature and film thickness

Indium oxide films with a thickness of 100 nm were deposited onto Corning 7059 glass substrates at room temperature. The films were prepared by the dc magnetron sputtering technique using a variety of sputtering powers and sputtering atmospheres. The structural parameters of the films as determined by XRD analysis and the optical band gap were found to be dependent on the sputtering power during their preparation. The ozone sensing properties of the indium oxide films were investigated following an activation with UV light and as a result a sensitivity of 10 5 to 10 6 was achieved. For films sputtered with a deposition rate of 0.4 A/s and with 100% oxygen in plasma during the sputtering process, the highest sensitivity was achieved.

The influence of deposition parameters on room temperature ozone sensing properties of InOx films

http://esperia.iesl.forth.gr/~ppm/PUBLICATIONS/ASSc_ZnO_PLD_2006.pdf

Thickness influence on surface morphology and ozone sensing properties of nanostructured ZnO transparent thin films grown by PLD

Indium oxide thin films have been prepared by thermal oxidation of vacuum‐deposited indium thin films in air in an open furnace at about 600 K. These indium oxide thin films prepared by thermal oxidation have been examined for optical transparency by measuring their optical absorbance as a function of wavelength. From the optical absorption data, optical band gap and the nature of the forbidden energy gap in the indium oxide thin films have been determined. Electrical conductivity measurements have also been carried out on the above oxide films as a function of temperature during heating and cooling cycles in vacuum. It is found that after the first heating, electrical conductivity increases to a significant extent due to removal of point defect clusters due to annealing which contribute to both carrier generation and scattering. From the thermoelectric power measurements carried out, it has been concluded that electrons are the majority carriers in these indium oxide thin films.

N. Lakshminarayan

Papers

Optical and electrical investigations of indium oxide thin films prepared by thermal oxidation of indium thin films