Effect of thermal annealing on the microstructural and electrical properties of Al-doped ZnO thin films grown on n-Si (1 0 0) substrates

Transmission electron microscopy (TEM) images for the Al-doped ZnO (AZO) films grown on n-Si (1 0 0) substrates and annealed for 10 min at 900 and 1000 °C showed that an amorphous phase region appeared in the grain boundaries of the AZO thin films by tilting the TEM specimen and that the amorphous phase did not show the constrast variation with change in the zone axis of the specimen. High-resolution TEM images revealed that the single grains existing around the amorphous region contained a higher dislocation density in comparison with the polycrystalline region. Hall effect results showed that the mobility of the annealed AZO thin films was smaller than that of the as-grown AZO thin films and that the resistivity of the annealed AZO thin films was larger than that of the as-grown AZO thin films.