Synthesis, structural and electrical properties of annealed ZnO thin films deposited by pulsed laser deposition (PLD)

• ZnO thin films were prepared by using PLD.
• The XRD reveal the presence of hexagonal wurtzite structure of ZnO films.
• These annealed films are promising materials for electrical component applications.

The effects of annealing times on the structural and electrical properties of ZnO thin films by XRD, FTIR, and dc conductivity were investigated. The XRD reveal the presence of hexagonal wurtzite structure of ZnO with preferred orientation (0 0 2). The grain sizes were found to be in the range 7.765–15.905 nm. The values of optical phonon frequency (νo) were obtained to be 1.26–1.44 × 1013 Hz. The electrical conductivity shows that all samples are semiconductor and it decreases with increasing annealing times. The calculated activation energy for the films was found to be 0.0322–0.126 eV. The increase in electric conductivity in the films annealed at 400 °C for 1 h compared to that of the film annealed at 400 °C for 4 h can be attributed to the decrease in grain boundary scattering due to the reduction in grain size.