STRUCTURE DETERMINATION OF ULTRATHIN NBSE2 FILMS BY GRAZING-INCIDENCE X-RAY-DIFFRACTION

Grazing incidence x-ray diffraction (GID) technique was applied to determine the three dimensional structures of NbSe2 films grown by van der Waals epitaxy. Atomic arrangements along the surface normal in nm-order films were established from the analysis of Bragg rod profiles measured with GID. The obtained structural polytypes of the films grown on HOPG and Se terminated GaAs(111BAR) were 2Hb and a mixture of 2Hb and 3R, respectively. This result indicates that the polytypes are controlled by the substrate materials in van der Waals epitaxy.