Structural properties of ZnO: In thin films prepared by sol-gel spin-coating technique

ZnO: In thin films with thickness varying in the 210-240nm range were prepared on quartz substrates by sol-gel spin-coating technique. The structural properties of these thin films (In/Zn = 0, 1, 2, 3 and 5at%) were studied by grazing incidence X-ray diffraction, conventional X-ray diffraction, Fourier transform infrared spectroscopy, atomic force microscopy and photoluminescence. It is found that the ZnO: In thin films are composed of the unstressed bulk layer packed up by large grains with (002) plane and the surface layer by small grains with (002) and (103) planes, and a proper In doping concentration can improve structural properties of ZnO thin films. The analytic results were further proved by grazing incidence X-ray diffraction at different incidence angles (a = 1, 2, 3 and 5').