Optical and electrical properties of aluminum-doped ZnO thin films grown by pulsed laser deposition

Transparent aluminum-doped zinc oxide (AZO) thin films were deposited on quartz glass substrates by pulsed laser deposition (PLD) from ablating Zn-Al metallic targets. The structural, electrical and optical properties of these films were characterized as a function of Al concentration (0-8 wt.%) in the target. Films were deposited at a low substrate temperature of 150 °C under 11 Pa of oxygen pressure. It was observed that 2 wt.% of Al in the target (or 1.37 wt.% of Al doped in the AZO film) is the optimum concentration to achieve the minimum film resistivity and strong ultraviolet emission. The presence of Al in the ZnO film changes the carrier concentration and the intrinsic defects.