Deposition and characterization of laser ablated poly(p-phenylene sulfide) thin films

Thin films of poly(p-phenylene sulfide) [PPS], were deposited by pulsed laser deposition with a doubled Nd:YAG laser (λ=532 nm) on Si (100) and quartz substrates at temperatures above and below the glass transition temperature (Tg) of the polymer. SEM micrographs of the films showed a decrease of particulate size with increasing substrate temperature. An absorption band edge at 3.4 eV in the UV–VIS spectrum of the deposited film indicated that they were polymeric as well as insulating. FTIR spectra of films deposited at various substrate temperatures mimicked all characteristic vibrational frequencies observed in pristine bulk samples. Low-angle X-ray diffraction patterns and FTIR spectral analysis of the deposited PPS films confirmed that the crystallinity was enhanced when the substrate temperature during deposition exceeded Tg. X-ray photoelectron spectroscopic (XPS) investigations of the C1s spectra of the as-deposited film on Si (100) revealed oxidation of the surface with the formation of sulfone, sulfoxide, C–O and CO. Ar+ ion sputtering with a 4 keV beam at 1 μA beam current removed ∼2 nm of the surface film and completely eliminated the sulfone peak from the XPS spectra, retaining a very negligible oxide component.