Self-assembly of silicon nanowires studied by advanced transmission electron microscopy

• Main Authors: Marta Agati, Guillaume Amiard, Vincent Le Borgne, Paola Castrucci, Richard Dolbec, Maurizio De Crescenzi, My Alì El Khakani, Simona Boninelli
• Format: Article
• Language: English
• Published: Beilstein-Institut 2017-02-01
• Series: Beilstein Journal of Nanotechnology
• Subjects: silicon nanowires; transmission electron microscopy; vapor–liquid–solid growth
• Online Access: https://doi.org/10.3762/bjnano.8.47

Scanning transmission electron microscopy (STEM) was successfully applied to the analysis of silicon nanowires (SiNWs) that were self-assembled during an inductively coupled plasma (ICP) process. The ICP-synthesized SiNWs were found to present a Si–SiO2 core–shell structure and length varying from ≈100 nm to 2–3 μm. The shorter SiNWs (maximum length ≈300 nm) were generally found to possess a nanoparticle at their tip. STEM energy dispersive X-ray (EDX) spectroscopy combined with electron tomography performed on these nanostructures revealed that they contain iron, clearly demonstrating that the short ICP-synthesized SiNWs grew via an iron-catalyzed vapor–liquid–solid (VLS) mechanism within the plasma reactor. Both the STEM tomography and STEM-EDX analysis contributed to gain further insight into the self-assembly process. In the long-term, this approach might be used to optimize the synthesis of VLS-grown SiNWs via ICP as a competitive technique to the well-established bottom-up approaches used for the production of thin SiNWs.