Effect of annealing on the properties of Bi doped ZnO thin films grown by spray pyrolysis technique

•Spray deposited Bi doped ZnO (BZO) films were annealed at different temperatures.•Crystallinity of the BZO films improved with increase in annealing temperature.•Transmittance of BZO films increases with annealing.•Hall measurement confirms the improvement in electrical conductivity of BZO films.

The effect of annealing temperature on the structural, optical and electrical properties of transparent and conducting Bi doped ZnO (BZO) films deposited on glass substrate by spray pyrolysis technique was investigated. The BZO thin films were annealed in the temperature range from 450 °C to 550 °C for 4 h in air atmosphere. The grain size of the BZO films increased with increasing annealing temperature. The annealed BZO films were electrically stable and there was a drastic change in the electrical conductivity after annealing. The films annealed at 500 °C showed better conductivity and optical transmittance.