Precise morphology control of in-plane silicon nanowires via a simple plasma pre-treatment

Silicon nanowires (SiNWs) are advantageous building blocks to explore a wide range of high performance nanoelectronics and photonics devices. In-plane solid-liquid-solid (IPSLS) SiNWs, grown by metal catalyst droplets that absorb hydrogenated amorphous silicon (a-Si:H) thin film to produce crystalline SiNWs, are particularly suitable for planar device fabrication and integration. Here, we explore a new growth control dimension to tailor the geometry of the in-plane SiNWs from island-chain to zigzag and to straight morphologies by using a simple plasma modification of the a-Si:H thin film precursor. This unique capability is due to fact that the Gibbs energy and bonding status of the a-Si:H layer can be largely modified by the plasma treatments at various substrate temperatures, which in turn have a huge impact on the growth balance condition of the SiNWs and consequently on their morphologies. These results highlight a facile and yet highly effective strategy to tailor the morphologyof in-plane SiNWs that will find important applications in fabricating nanoelectronic, sensor and logic devices.