Development of Al doped ZnO as TCO by Atomic Layer Deposition

Aluminium doped Zinc Oxide (AZO) thin films were deposited on SiO₂/Si and glass substrates by Atomic Layer Deposition (ALD) in the temperature range of 150 °C - 250 °C. X-ray diffraction revealed the formation of c- axis oriented wurtzite phase of undoped ZnO films. The crystallinity of the films decreased with increasing pulse ratio of Zn:Al which indicating the incorporation of Al³⁺ in the ZnO lattice. The minimum achievable resistivity (ρ) of the films was 4.8×10-3 Ω-cm with transparency > 80% in the visible range. The bandgap of the materials shows a blueshift with the increasing Al doping concentration.