Vibrational spectra of polysilane alloys Available to Purchase

Infrared (IR) absorption and Raman spectra are measured for glow‐discharge‐produced, wide‐optical‐gap binary Si:H alloys containing a number of polysilane (SiH₂)_n groups (polysilane alloys). The highly resolved IR stretching band revealed double peaks, at 2100 and 2122 cm⁻¹, which correspond to an exterior SiH₂ and an interior SiH₂, respectively, in a 3/4 Si(SiH₂)_nSi 3/4 group. This result provides evidence for the existence of (SiH₂)_n (n≥3) groups. Nonlinearity of the (SiH₂)_n wagging absorption strength with the number of SiH₂ units in the alloy is observed in the IR spectra. This is related to a change in the polymerization degree of a (SiH₂)_n chain. Raman scattering intensity in the 50–400 cm⁻¹ range is lower than that for conventional hydrogenated amorphous silicon alloys, suggesting a reduction in the number of Si loops arising from (SiH₂)_n chain formations. The change in the polymerization degree as a function of substrate temperature during deposition and the annealing temperature are also discussed.