Effect of post sputter annealing treatment on nano-structured cadmium zinc oxide thin films

Thin films of cadmium zinc oxide (CdZnO) were deposited on glass substrates by reactive dc magnetron sputtering and post sputter annealed at different temperatures: 350 °C, 400 °C, 450 °C, 500 °C and 550 °C. These films were characterized by glancing angle x-ray diffraction, field emission scanning electron microscopy, photoluminescence, UV–vis–NIR spectroscopy and Hall measurements. The structural results revealed that all these films exhibit hexagonal wurtzite structure with complete c-axis orientation in (002) plane. The transmittance of these films increased with the post sputter annealing treatment and minimum band gap observed for the film that was annealed at 500 °C. The carrier concentration and Hall mobility increased with post sputter annealing, while electrical resistivity decreased with the narrowing optical band gap and increase in the crystallite sizes. - Highlights: • CdZnO is proposes as a TCO material due to its low ρ (3 Ω cm) and high T (90%). • The lowest E_g of 2.75 eV was observed at 500 °C of post annealing temperature. • CdZnO thin films have hexagonal wurtzite structure with the orientation (002). • It shows n-type nature from Hall measurements.