Influence of power ramps on the physical properties of AZO thin films deposited at room temperature by RF magnetron sputtering technique

Aluminum-doped zinc oxide (AZO) thin films were deposited on glass substrates at room temperature by RF sputtering technique. Power ramps between 125 and 105 W were applied with a step of 4 W by intervals of 15, 7.5 and 1.8 min, for 180 min at 1.60 Pa. In this study, we investigated the structural, morphological, electrical, and optical properties of AZO films. X-ray Diffraction analysis showed that the films have a wurtzite-type hexagonal crystalline structure with a preferential crystallographic orientation (002) normal to the c axis. The average transmittance is greater than 76% for the wavelength range in the visible spectrum. The bandgap values were found between 3.32 and 4.01 eV, and refractive index was 1.79–2.60. Atomic force microscope measurements show homogeneous films with a roughness between 17–22 nm. A minimum resistivity value of 2.0 × 10⁻³ Ω cm was obtained for the film by using a power ramp of 4 W/1.8 min.