ArF Laser-Induced Chemical Vapor Deposition of Polythiene Films from Carbon Disulfide

Abstract

Laser photolysis at 193 nm of gaseous carbon disulfide into CS and S in the absence and excess of N 2 is controlled by two-photon-induced depletion of CS 2 and affords chemical vapor deposition of (CS) n polymer and S n . The proposed polymerization mechanism of CS is explained by an intermediacy of C 2 S 2 species. The (CS) n polymer contains S-centered radicals that are stable in air and withstand heating in a H 2 atmosphere. Its structure is contributed by >CdS, >CdC<, S 2 CdCS 2, , -C-(CdS)sS-, -Ss(CdS)sS-, and C-Ss SsC configurations whose relative extent depends on irradiation conditions: more CdS bonds (and fewer C-S bonds) are formed at higher CS 2 pressure, in the excess of N 2 and with lower laser fluences. The extent of the S 2 CdCS 2 units decreases, and that of >CdC< units increases, upon mild polymer heating. The polymer deposited in the absence of N 2 consists of unique 100-200 nm sized hollow spheres.

UV Laser Deposition of SiS/Poly(thiacarbosilane) Composites and their Conversion to SiO/Poly(thiacarbosiloxane) Composites

“…We have previously shown that laser-induced codecomposition of metal and chalcogene progenitors, leading to gas-phase formation of metal and chalcogene clusters, is suitable for chemical vapor deposition of nanosized metal chalcogenides. [10,[18][19][20] Continuing our studies on laserinduced chemical vapor deposition of polythiene [6] and CS 2 /C 2 H 4 co-polymer, [8,9] we now report on ArF laser irradiation of gaseous carbon disulfide-silane mixtures and show that this process affords chemical vapor deposition of SiS-containing poly(thiacarbosilane)s. These materials are the first example of SiS/polymer composites.…”

“…CS þ S, [1][2][3][4][5] ), or be collisionally de-excited by SiH 4 (and N 2 ) molecules. The former route implies formation of elemental sulfur and polythiene [6] and the latter is in line with the formation of a (CS 2 ) n polymer (e.g. [8,9,23,24] [25,26] ) and decomposition of silylene (producing H 2 and H/Si agglomerates) together with reaction of silylene with CS 2 [27] and transient formation of silanethione [28] are other plausible reactions.…”

“…The films are partly soluble in CS 2 and their soluble and insoluble fractions differ in FT-IR spectra ( Figure 6) and composition. The soluble fractions have FT-IR spectra similar to those of polythiene films [6] and they do not at 470, 870, 1 060 and a 3 400-3 600 cm À1 relating, in the given order, to n(S-S), n(C --S) in -S-(C--S) -S-, n(SiOSi) and n(H-OÁÁÁH) modes. These data allow conclude that the insoluble fractions are C-S-S-C units-containing poly(oxocarbosilanes).…”

“…All the spectra, assigned after ref. [6,9,31] , are dominated by a very strong and broad band The sulfide shows [33] also absorption at 456 and 500 cm À1 , but these contributions are hidden by the dominant n(Si-S-Si) band.…”

“…ArF laser photolysis of gaseous carbon disulfide occurs via single-and double-photon excitation and results [1][2][3][4][5] in the transient formation of excited CS radical and S atoms that allow [6] chemical vapor deposition of a blend of polythiene (CS) n polymer and S n . This photolytic gas-phase photopolymerization of CS is a unique process that differs remarkably from the CS decay to a carbonaceous polymer through a heterogeneous wall reaction in the absence of the UV excitation source.…”