Electrical and Optical Properties of Zinc Oxide Thin Films Deposited by Magnetron Sputtering

The Al doped ZnO(ZnO: Al) films were deposited on glass substrates with direct current (DC) or radio frequency (RF) magnetron sputtering by using an alloy or ceramic target. The influence of the substrate temperature on the crystal structure, surface morphology, optical and electronic properties of the ZnO: Al films was investigated. Highly transparent ZnO: Al films with optical band gap of 3.25-3.29eV were deposited by sputtering a ceramic target. The X-ray diffraction results show that all ZnO: Al films grow in a hexagonal-wurtzite phase with highly caxis preferred orientation and the average crystal size increases upon the promotion of substrate temperatures. The resistivity of ZnO: Al films decreases with an increasing substrate temperature. The resistivity further decreases to 3.566x10(-3) Omega.cm with annealing in nitrogen.