Improved characteristics of sprayed CdO films by rapid thermal annealing

We report the influence of rapid thermal annealing (RTA) on optical, electrical and structural properties of sprayed undoped CdO thin films. XRD investigation revealed that as-grown films are polycrystalline in nature with cubic structure; and pronounced improvement in crystallinity of the films have been noticed after annealing. RTA-treated films showed preferred orientation in the (2 0 0) direction. The optical band gap was deduced from transmittance data for as-grown and annealed films and found to be 2.51 eV for as-grown film and ranged between 2.25 and 2.48 eV for annealed films. Figure of merit was calculated and found its maximum value (1.2 × 10−2 Ω−1) was for film annealed with of 6 min. Thermoelectric power (TEP) measurements revealed that the CdO films are having n-type conductivity. Furthermore, the activation energy was calculated for films from TEP data. The lowest electrical resistivity was found to be 6 × 10−4 Ω cm for CdO film annealed with time ≥6 min. The observed changes demonstrated that RTA is a viable technique for improving characteristics of sprayed CdO films.