ULTRASONIC SPRAY-ASSISTED CVD GROWTH OF HIGHLY TRANSPARENT AND CONDUCTIVE ALUMINUM-DOPED ZnO

Abstract

Zinc oxide [Formula: see text], undoped and Al-doped thin films have been synthesized by the ultrasonic spray-assisted chemical vapor deposition (USCVD) system. The films were deposited on glass substrates. The precursor solution was prepared dissolving zinc chloride in distilled water. First, the precursor concentrations were investigated and optimized before studying [Formula: see text] doped, after we have studied the [Formula: see text]-doped influence on [Formula: see text] films especially optical and electrical properties for use as a transparent conductive oxide (TCO) in solar cell electrodes. The characterizations have been carried out using X-ray diffraction technique, UV-vis spectrophotometry, Hall Effect measurement (ECOPIA), atomic force microscopy (AFM, VEECO Dimension [Formula: see text] and scanning electron microscopy (SEM). X-ray diffraction (XRD) results showed that [Formula: see text] and [Formula: see text]-doped [Formula: see text] films were crystallized in the hexagonal wurtzite structure with [Formula: see text] orientation. Optical measurements have shown that all films exhibit, along the visible range, high transmittance and that optical band gap depends strongly to [Formula: see text]-doped concentration. Hall-effect measurement indicates that the highest carrier concentration [Formula: see text] and the lowest resistivity [Formula: see text] are obtained for the [Formula: see text] AZO sample. The SEM shows that the microstructures of [Formula: see text] and [Formula: see text] are homogeneous and the AFM images prove their microcrystallinity with grains orthogonal to the film surface.