Photoconductivity Measurements in Nanostructured ZnO and ZnO:Al Films

Abstract

ZnO is a versatile material used in numerous applications, such as antireflective coatings, transparent electrodes for solar cells, gas sensors, varistors and electro and photoluminescent devices. One of the most important properties of ZnO is the photoconductivity in the UV, due to the band-gap energy. In this work, nanostructured pure and aluminium doped ZnO films were grown by sol-gel method. The precursor solutions were deposited with a different quantity of layers by spin-coating technique on SiO2 substrates. The films were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). Photoconductivity study of prepared films showed that layers also exhibit sensitivity in the visible spectrum besides a remarkable and usual sensitivity to UV. Performance of pure and doped ZnO films was compared. The UV sensitivity related to the film thickness was also studied.