Glancing-angle pulsed dc magnetron sputtered AZO thin films for TCO applications

Abstract

Aluminum-doped zinc-oxide (AZO) thin films were fabricated by pulsed dc magnetron sputtering with glancing-angle deposition (GLAD) techniques on silicon wafers and glass substrates. During the film deposition, the incident angle, α, between the particle flux and the substrate normal was carefully changed from 45° to 85°. The prepared samples were investigated for the film physical morphologies, crystallinity, optical transmission, and electrical properties based on the field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), UV-VIS-NIR spectrophotometry, and Hall-effect measurements, respectively. The microstructures evolved from the columnar structures to the inhomogeneous film structures as the deposition angle was increased. When the deposition angle was increased, the deposition rate was gradually decreased. All the prepared films illustrated the hexagonal structure with the (002) and (103) orientations. The average transmission of the AZO thin films in the visible range was above 80%. In addition, the best deposition conditions of the AZO thin films could be applied to the transparent electrodes for the solar cell applications.