Optical and electrical properties of (002)-Oriented ZnO films prepared on amorphous substrates by sol-gel spin-coating

Abstract

Zinc oxide (ZnO) films were prepared on amorphous quartz substrates by sol-gel spin-coating using Zn(CH3COO) 2 2H2O precursor. Isopropanol, ethanol and 2-methoxyethanol were used as solvents. The film drying temperature was kept constant at 200 °C and the annealing temperature was varied from 400 to 800 °C. Highly transparent and (002)-oriented hexagonal wurtzite-type ZnO films were obtained using isopropanol solvent. The ZnO films prepared at Tanneal = 600 °C showed the highest (002) preferential orientation, however it was not the significant feature to achieve low resistivity. The uniform and (002)-oriented ZnO films prepared at Tanneal = 400 °C display the highest transmittance (>93% in the visible region) and the lowest resistivity (7.1 Ωcm).