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Nano transparent conducting aluminum-doped zinc oxide (AZO) thin films were deposited on glass substrates by the magnetron sputtering technique. The thin films were characterized with X-ray diffractometer, scanning electronic microscopy, four-point probe and UVVisible spectrophotometer. The dependence of structural, morphological, optical and electrical properties on substrate temperature was investigated. The results show that all the thin films have hexagonal wurtzite structure with highly c-axis orientation. The structural and optoelectrical properties of thin films are observed to be subjected to the substrate temperature. The AZO thin film deposited at the substrate temperature of 370°C possesses the best optoelectronic properties, with the lowest resistivity of 6.12 9 10 -4 X cm, the minimum microstrain of 0.92 9 10 -3 , the highest average visible transmittance of 85.1 % and the maximum figure of merit of 1.03 9 10 4 X -1 cm -1 . The optical bandgap of thin films was estimated from Tauc's relation and observed to be an increasing tendency with the increment of the substrate temperature. Furthermore, the optical constants such as refractive index, extinction coefficient, dielectric constant, dissipation factor and optical conductivity were determined by the pointwise unconstrained optimization method, and the dispersion behaviour was studied by the Wemple-DiDomenico single-oscillator model.

In this work, three different sets of processing techniques (wet, dry, and combined treatments) were utilized to modify the surfaces of indium-tin oxide (ITO) substrates for polymer electroluminescent devices (PELDs), and the influence of surface treatments on the surface properties of ITO substrates were investigated by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), contact angle, and four-point probe. The surface energies of ITO substrates were also calculated from the measured contact angles. Experimental results show that the surface properties of the ITO substrates strongly depend on the surface treatments. Oxygen plasma treatment effectively improves the ITO surface properties since plasma decreases the surface roughness and sheet resistance, improves the surface stoichiometry and wetting. Furthermore, the PELDs with the differently treated ITO substrates as hole-injecting electrodes were fabricated and characterized. We observe that the optical and electrical characteristics of devices are greatly influenced by the surface treatments on ITO substrates. Oxygen plasma treatment decreases turnon voltage, increases brightness and efficiency, and thereby improves the device performance of PELDs.

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