Deposition of aluminum-doped zinc oxide films by RF magnetron sputtering and study of their structural, electrical and optical properties

摘要

Highly oriented undoped and aluminum-doped ZnO (AZO) films in the (002) direction were prepared by RF magnetron sputtering on glass substrates with specifically designed ZnO targets containing different amounts of Al(OH)_3 powder as doping source. A systematic study of the influence of deposition parameters such as Al(OH)_3 content in the target, the target-substrate distance (D_(ts)), deposition time and substrate temperature on the structural, electrical and optical properties of the as-grown AZO films was carried out. XRD shows that AZO (002) crystal grew parallel to the substrate. With increasing D_(ts) the growth rate increased, while the substrate temperature did not affect the growth rate. The as-grown AZO films not only have an average transmittance of >85% in the visible region, but also have an optical bandgap between 3.2 and 3.64 eV, depending on the sputtering parameters. The resistivity of the film deposited at D_(ts)=45 mm from a 4 wt.% Al(OH)_3-doped ZnO target was approximately 9.8X10~(-2) Ω cm, showing semiconductor properties.