Effect of annealing temperature on the characteristics of ZnO thin films

► Effect of annealing temperature on characteristics of sol-gel driven ZnO thin film was studied.► Granular shape of ZnO crystallites was observed on the surface of the films annealed below 750 °C.► Nodular shape of crystallites was formed upon increasing the annealing temperature above 850 °C.► The Schottky diode behavior diminished upon increasing the annealing temperature above 850 °C.