DEPOSITION AND OPTOELECTRONIC PROPERTIES OF ITO (In2O3:Sn) THIN FILMS BY JET NEBULISER SPRAY (JNS) PYROLYSIS TECHNIQUE

Nanocrystalline ITO thin films were deposited on glass substrates by a new spray pyrolysis route, Jet nebuliser spray (JNS) pyrolysis, for the first time at different substrate temperatures varying from 350 to 450 C using a precursor containing indium and tin solution with 90:10 at% concentration. The structural, optical and electrical properties were studied as a function of temperature. XRD showed that the deposited films were well crystallised and polycrystalline with cubic structure, having (222) preferred orientation. The optical band gap values calculated from the transmittance spectra of all the ITO films showed a blue shift of the absorbance edge from 3.60 to 3.76 eV, revealing the presence of nanocrystalline particles. AFM showed uniform surface morphology with very low surface roughness values. XPS showed the formation of ITO films with In3+ and Sn4+ states. TEM showed the nanocrystalline nature with grain size about 12-15 nm, and SAED confirmed the cubic structure of the ITO films. Electrical parameters such as resistivity, mobility and carrier concentration were 1.82 x 10 exp(-3) ohm.cm, 8.94 cm2/Vs and 4.72 x 10 exp(20)/cm3, respectively, for ITO film deposited at 400 C. These results show that the ITO films, prepared using the new JNS pyrolysis technique, have device quality optoelectronic properties when deposited under the proposed conditions at 400 C.