TUNGSTEN DISELENIDE THIN-FILMS SYNTHESIZED ON TUNGSTEN FOILS

Selenium thin films were evaporated onto a tungsten layer deposited by r.f. sputtering onto tungsten substrates. WSe2 layers were synthesize d by annealing these samples in a vacuum-sealed Pyrex tube. The layers obtained were investigated by scanning electron microscopy, microprob e analysis, X-ray diffraction and X-ray photoelectron spectroscopy. St oichiometric layers are obtained after appropriate post-annealing. The crystallites grow preferentially with their c axis perpendicular to t he plane of the substrate and the films crystallize in the hexagonal s tructure. The texture of the films increases with increasing annealing time and the surface of the films is fairly homogeneous. The layers p resent good adherence properties.