Silicon-catalyzed growth of amorphous SiOx nanowires by continuous-wave laser ablation of SiO in high-pressure gas

Continuous-wave laser ablation of an SiO target was performed to grow nanowires (NWs) in high-pressure (up to 0.90 MPa) Ar, N 2 , and O 2 gas. In Ar gas, the fraction of the NWs in deposits was changed significantly by the Ar pressure. As Ar pressure increased, thicker NWs with diameters of up to 80 nm were grown. The NWs were amorphous SiO x and attached with sphere-like nanoparticles (NPs) at their tips. The tip NPs were composed of crystalline Si covered with thin amorphous SiO x layers. Similar NW growth occured in N 2 gas. However, only amorphous NPs were generated in O 2 gas. On the basis of liquid-like molten SiO x NPs containing a portion of a Si phase formed by a disproportionation reaction of SiO x , we discuss the nucleation and growth of the NWs through supersaturation and anisotropic precipitation of SiO x .