Influence of Substrate Temperature on the Properties of Al-Doped Zinc Oxide Films Prepared by DC Reactive Magnetron Sputtering

Transparent and conductive c-axis oriented aluminum-doped zinc oxide (AZO) films have been prepared on glass substrate by dc reactive magnetron sputtering process. The structural, optical and electrical properties of the films were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), UV-Visible spectrophotometer and Hall effect measurement system. As the substrate temperature increased, the results showed that grain size of the AZO films gradually increased, the films had a strong c-axis oriented and the crystallization of films became better. The absorption edge first shows a red shift, and then switches to the blue shift with increasing substrate temperature. Optical band gap of AZO films first decreases and then increases with increasing substrate temperature. Resistivity of AZO films decreases with increasing substrate temperature but the rate of decline of resistivity becomes slow after substrate temperature reaches 250 °C. The carriers concentration of AZO films increases with substrate temperature increase.