Polymeric precursor for solution-processed amorphous silicon carbide
Amorphous silicon carbide (a-SiC) films are deposited via solution-based processes using a polymeric precursor solution consisting of polydihydrosilane with pendant hexyl groups. Unlike conventional polymeric precursors, this polymer neither requires catalysts nor oxidation for its synthesis and cross-linkage. Therefore, our polymeric precursor provides sufficient purity for the fabrication of solution-processed semiconducting a-SiC. Polymer-to-ceramic conversion is systematically investigated under various pyrolysis temperatures ranging from 320 °C to 420 °C. The polymer primarily undergoes cross-linking at temperatures above 150 °C with increasing polymer fraction; this cross-linking is followed by carbon atoms being incorporated into an amorphous network at 380 °C. The incorporated carbon atoms in the film are predominantly in the sp3-bonding state with almost no amorphous graphite-like sp2 CC clusters, leading to marked changes in the film's properties. The conductivity values of the resulting a-SiC films are comparable with those of semiconducting a-SiC films prepared using vacuum-based deposition.