Electrical and structural properties of annealed ZnO:B thin films

•The post annealing properties of Boron doped ZnO (BZO) films have investigated by means of experimental and theoretical methods.•The theoretical calculation results revealed the reason for improving crystallinity, and decreasing resistivity.•The electrical properties of BZO film was improved after a suitable annealing process.

We report an investigation of the properties of B-doped ZnO (BZO) films, which were deposited using pulsed direct-current magnetron sputtering, using both experimental and theoretical methods. The effect of the annealing temperature on the electrical and structural properties of BZO films was systematically investigated. The results show that, as the annealing temperature increased to 450 °C, the resistivity decreased owing to an improvement of the crystallinity and an increase in the charge carrier concentration. The films annealed at the optimum annealing temperature of 450 °C in an Ar atmosphere had the lowest resistivity of 2.39 × 10−3 Ω cm. As the annealing temperature was increased further, the carrier concentration decreased, leading to an increase in the resistivity. Our calculations show that, following annealing, the configuration changed from B atoms substituted for Zn atoms (i.e., BZn) to B-doped tetrahedral interstitial sites (i.e., BT). The BT configuration resulted in improved crystallinity and larger charge carrier concentration, both of which contributed to a decrease in the resistivity.