Influence of annealing atmosphere on optical and electrical properties of Ga and F co-doped ZnO thin films prepared by sol-gel spin-coating

Ga and F co-doped ZnO (GFZO) thin films were prepared on quartz substrates via the sol-gel spin-coating method, followed by annealing in O 2 , Ar, N 2 , and H 2 atmosphere. The effects of annealing atmosphere on the structure, optical transmission, electrical properties, and thermal stability of GFZO films were systematically investigated. All GFZO films exhibited a typical wurtzite structure with a c-axis preferential orientation. The average optical transmittance of GFZO films annealed in Ar, N 2 , and O 2 atmospheres exceeded 90% in the visible region, while that of the H 2 -annealed sample was about 60%. The resistivity values of GFZO films annealed in Ar, N 2 , and H 2 atmospheres ranged from 1×10 -3 to 3×10 -3 Ω·cm at room temperature, whereas the film annealed in O 2 showed a much higher resistivity of 7.887×10 5 Ω·cm. Notably, the GFZO thin films annealed in Ar or N 2 atmosphere can maintain a low resistivity of 8×10 -3 Ω·cm even at 500 °C while retaining excellent thermal stability. With high optical transmittance, low electrical resistivity, and outstanding thermal stability, the Ar and N 2 annealed GFZO thin films are highly suitable for transparent conductive thin film applications.