“…Annealing temperature or heat treatment is very effective to improve the electrical and optical properties [6e9]. Also, annealing effect can enhance the film properties, such as crystal quality, electric and luminescence behavior by improvement of crystallinity of the films and increase in grain sizes [10,11]. Poor crystalline quality may cause a reduction in the relaxation time and mobility as a result of increased point defects, grain boundaries and lattice distortion [12,13].…”