Growth of high-quality bio-friendly ZnO:Ga thin films by pulsed laser deposition technique

Zinc oxide (ZnO) is a versatile material that exhibits a variety of interesting properties, including a wide electronic band gap, high exciton binding energy, and biocompatibility. Due to this unique combination of properties, it finds application in a vast range of areas, spanning from ultraviolet lasers to transparent semiconductors and from transparent magnets to sunscreens. ZnO can also be used to form self-cleaning surfaces that can kill harmful pathogens with exposure to sunlight. In order to create these self-cleaning surfaces, a thin coating of the material must be prepared on the surface. In this study, we report the growth of Gallium (Ga) doped ZnO films on sapphire. To grow these films, we used a pulsed laser deposition technique. In this technique, ultra-high power laser pulses from an excimer laser were made incident on a solid ZnO:Ga target. This led to the ablation of the target material resulting in the formation of a plasma plume which got deposited on the sapphire substrate that was kept at a 5 cm distance from the target. The temperature of the sapphire substrate was varied from 100 C to 700 C. Films were characterized using several different techniques and a correlation was established between deposition parameters and the properties of the films.