Initial nucleation and growth of in-plane solid-liquid-solid silicon nanowires catalyzed by indium

We report a systematic investigation of the initial nucleation and growth of in-plane solid-liquid-solid (IPSLS) silicon nanowires (SiNWs), catalyzed by indium (In) drops prepared in situ by a H-2 plasma superficial reduction of indium tin oxide in a plasma-enhanced chemical-vapor deposition system. A supersaturation of Si atoms in the In catalyst drop is first established by the absorption of the hydrogenated amorphous silicon (a-Si:H) layer coating the catalyst drops. The initial nucleation of Si seeds in the catalyst drop is found to happen preferentially along the catalyst bottom edge and the lateral growth of SiNW is actually triggered by the largest Si seed that tilts the catalyst drop into the opposite direction to form new absorption edge with nearby a-Si:H layer. We show that the ratio of the a-Si:H layer thickness to the catalyst diameter is a key controlling factor for achieving a high-growth activation rate of the lateral IPSLS-SiNWs.