Si 1-xC x nanowires (NWs) were synthesized by varying the ratio of SiH 4 and CH 3SiH 3 gases using a vapor-liquid-solid (VLS) procedure using Au as a catalyst. The growth rate of the Si 1-xC x NWs and the change in the wire shape from straight to helical near the Au tip were found to be closely related to the ratio of the CH 3SiH 3 content. The large concentration of C in the Si 1-xC x NWs was proportional to the CH 3SiH 3 content, overcoming the extremely low solubility of C in Si, resulting in an interstitial incorporation of C atoms in the wire. This incorporation can be attributed to the cleavage of Si-C bonds in the CH 3SiH 3 compound through the Au catalyst (an Au-Si liquid-state cluster of about 70-100 nm) during wire growth by the VLS method. Simultaneously supplying CH 3SiH 3 and SiH 4 gases enhanced the diffusion of Au atoms from the tip to the sidewall of the wire, while also deforming the shape of the Au tip. When the CH 3SiH 3 gas was increased to 1.5 sccm, the number of Au nanoparticles (2-3 nm in size) at the lateral surface induced a surface plasmon resonance (SPR) and improved the optical conductivity (σ) of the Si 1-xC x NWs. For 2 sccm of CH 3SiH 3, a remarkable increase in the number of C atoms incorporated in the Au nanoparticles along the sidewall red shifted the SPR peak, suggesting that the SPR can be modulated by the Au-C interactions in the nanoparticles.
All Science Journal Classification (ASJC) codes
- Materials Chemistry