THICK (DELTA-GREATER-THAN-OR-EQUAL-TO-300 NM) WS2 FILMS OBTAINED ON UNPOLISHED GLASS SUBSTRATES

WS, films, with a thickness higher than 0.3 mu m, synthesized by solid state reaction between the constituents deposited in thin film form a re quite difficult to obtain on polished glass substrates because the films peeled off from the substrate. It is shown that films with a thi ckness of 1 mu m can be obtained with this technique by using unpolish ed glass substrates. The films obtained are nearly stoichiometric and are crystallized in the 2H-WS2 hexagonal structure. The rugosity of th e glass substrate induces some disorder in the films. The grain size i s quite small (D less than or equal to 10 nm) and although the majorit y of the crystallites have their c axis perpendicular to the plane of the substrate, there are always crystallites with other orientations. These structural results imply that the conductivity of the films is c ontrolled by grain boundaries effects.