Differences between (103) and (002) X-ray diffraction characteristics of nanostructured AZO films deposited by RF magnetron sputtering

This study examines the existence of a (103)-oriented surface region and the differences between the (002)-oriented bulk region of AZO thin films deposited by semi-industrial RF magnetron sputtering. The effects of deposition temperature on the structural characteristics of these two well-defined regions are independently investigated over a range of deposition temperatures from 100 degrees C to 200 degrees C, using grazing - incidence X-ray diffraction and conventional theta/28 X-ray diffraction. Two different X-ray diffractograms were identified, one in the (103)-oriented dominant plane (associated with lateral growth) to examine the superficial characteristics and one in the (002)-oriented dominant plane to examine the bulk characteristics. Secondary electron microscopy and atomic force microscopy were applied to confirm the surface characteristics of the AZO films, and it was found that the deposition temperature strongly affects the nanostructure of the deposited films. Finally, the influence of the surface and bulk nanostructure on the electronic and optical characteristic is discussed. The optimal deposition temperature was determined to be T-d = 175 degrees C, at which high-quality nanocrystalline AZO thin films were obtained with a remarkable resistivity of rho = 2.48 x 10(-4) Omega cm and an average transmittance of T similar to 93%.