3.3. Surface morphology
The surface microstructures of the AZO films were measured by FESEM. Fig. 5(a–c) presents the typical FESEM images of AZO films formed at various magnetic fields from 0 to 6 mT respectively. The applied magnetic field makes the films exhibit uniform grain growth with improved grain size and homogeneous surface morphology. From Fig. 5(a), AZO-0 films showed that it has smaller grains over the entire film. On the other hand, it can be seen from the Fig. 5(b) and (c) that the films formed at AZO-3.0 and AZO-6.0 condition shown the uniform distribution of grains with improved grain size as compared to the films prepared under magnetic field of 0 mT (AZO-0). With the increase in the strength of magnetic field from 0 to 6.0 mT, the number of ions impinging on the substrate will increase. This may lead to increase in grain size with increasing of substrate temperature, which indicates the improvement in the crystalline nature of the films. Furthermore, variation in grain size from FESEM analysis is consistent with the variation in crystal growth towards (002) direction from XRD. The variation in grain size with applied magnetic field was closely related to the film growth in preferential (002) direction. As the films formed with higher intensity of (002) reflection are connected to the decreasing tendency in FWHM. The changes in FWHM inversely proportional to the variation in grain size.