X-ray diffraction methods for diagnostics of surface and nanolayers of crystalline structures (review)

X-ray diffraction methods for investigation of thin surface layers of crystals and characterization of the structures containing nanolayers are considered: double- and triple-crystal diffractometry, asymptotic diffraction, and diffraction under conditions of total external reflection of X-rays. Theoretical foundation of the methods and conditions of their experimental implementation are described and exemplified.