Thin films may cause probelems, because (depending on the film thickness) there is only a quite limited number of lattice planes that contribute to Bragg peaks in a diffractogram, and thus the observed peaks are broadened and their intensity is small. The intensity may be enhanced by using a grazing incidence geometry instead of the usually applied Bragg-Brentano (theta - 2 theta) geometry. In such an asymmetric  geometry and an incidence angle close to the critical angle of total reflection, the surface sensitivity is substantially enhanced, and the chance to get clear diffraction data is substantially better! So give it a try! Kind regards, Dirk

P.S: LEED may in addition be only possible for almost perfect (monocrystalline)  film materials or epitaxial layers, in the case of polycrystalline films LEED is not a good option!

I think it is possible. At least it is working with semicunductor superlattices, where one can see the structure in XRD spectrum when the quality is good. Probably just the LEED can be usefull as well.

Thin films may cause probelems, because (depending on the film thickness) there is only a quite limited number of lattice planes that contribute to Bragg peaks in a diffractogram, and thus the observed peaks are broadened and their intensity is small. The intensity may be enhanced by using a grazing incidence geometry instead of the usually applied Bragg-Brentano (theta - 2 theta) geometry. In such an asymmetric  geometry and an incidence angle close to the critical angle of total reflection, the surface sensitivity is substantially enhanced, and the chance to get clear diffraction data is substantially better! So give it a try! Kind regards, Dirk

P.S: LEED may in addition be only possible for almost perfect (monocrystalline)  film materials or epitaxial layers, in the case of polycrystalline films LEED is not a good option!

One should add that the grazing angle geometry requires some modifications of the setup. On the tube side you should use a smaller aperture than with Bragg-Brentano, in order to narrow the inciding beam. On the detector side you should use a long Soller slit instead of the normal aperture system. The optimal Theta-Angle depends on the surface roughness of the film; try something around 1 or 2 degrees. Important: Invest some time! The quality of the patterns will rise significantly, if you do long-term measurements with dwell times of more than 10 seconds per 0.02° step.

In addition to all the contributors, I upvote the GIXRD. If the project is scientifically sound, why not to write a proposal for a beamtime at a synchrotron? There are experimental stations available for such kind of a project, optimized for grazing incidence of X-rays. Otherwise, one may use a low-energy electron microscope, which  can be used for determination of thin films structure even in the case of polycristalline films.

Best