PLASMA CHEMICAL-VAPOR-DEPOSITION OF A-C-S-N-H FILMS USING ORGANOISOTHIOCYANATES AS NOVEL SINGLE-SOURCE PRECURSORS

Amorphous C:S:N:H thin-film materials were produced from methyl, propy l-, allyl-, and phenyl isothiocyanate source compounds in plasma chemi cal vapor deposition (PCVD). The PCVD process was investigated in term s of the deposition yield and pressure increase in the reactor. These parameters provide insight into the mechanism of plasma activation of the organoisothiocyanates. The films are characterized in terms of the ir structure, elemental composition, optical absorption and electrical conductivity. The ultraviolet-visible (UV-VIS) spectral data account for the presence of two optical gaps in the examined materials. The li ght absorption is related to the excitation of electrons with a contri bution by the localized states of molecular nature, which contain pi-b onds. The materials, owing to their rather low conductivities (not exc eeding 10(-11) S m(-1)), can be classified as dielectrics. The thermal treatment of the films in nitrogen was found to increase the conducti vity by three orders of magnitude. The films reveal a substantial phot oconductivity effect which appears to be sensitive to the light wavele ngth. The evaluated quantum yield values are 10(-5)-10(-4) el. quant(- 1).