Synchrotron radiation photoabsorption and photoemission spectroscopy for thermal-induced reoriented Si polymer

The effect of laser annealing on electronic structures and molecular orientation for poly(dimethylsilane) {PDMS, [Si(CH3)2]n} has been studied by synchrotron radiation photoemission and photoabsorption spectroscopy. Prior to annealing, PDMS powder was mounted on the basal plane of highly oriented pyrolytic graphite. Both Si 1s X-ray photoemission spectroscopy and near-edge X-ray absorption fine structure spectroscopy (NEXAFS) at Si 1s edge show that electronic structures have been modified due to annealing. Furthermore, the angle-dependent NEXAFS spectra clearly indicate that the annealed products maintain a specific orientation. Interestingly, no such kind of orientation is present in as-received PDMS powder as no angle-dependency is observed before annealing.