Room Temperature Growth of Silica Nanowires on Top of Ultrathin Si Nanowires Synthesized with Sn‐Cu Bimetallic Seeds. Issue 22 (7th October 2021)

• Record Type: Journal Article
• Authors: Wang, Weixi; Ngo, Éric; Florea, Ileana; Foldyna, Martin; Roca i Cabarrocas, Pere; Maurice, Jean-Luc
• Is Part Of: Physica status solidi. Volume 218:Issue 22(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-10-07
• Subjects: Cu-based bi-metallic catalysts -- plasma-enhanced chemical vapor deposition -- silica nanowires -- silicon nanowires -- transmission electron microscopy; Solid state physics -- Periodicals; Solids -- Industrial applications -- Periodicals; 530.41
• DOI: 10.1002/pssa.202100409
• Languages: English
• ISSNs: 1862-6300

Abstract

Abstract : Si nanowires (NWs) are grown by the vapor–liquid–solid method using Cu–Sn bimetallic catalysts in a plasma‐enhanced chemical vapor deposition (PECVD) reactor. The microstructure of the NWs is analyzed by transmission electron microscopy and energy‐dispersive X‐ray spectroscopy. An amorphous SiO2 region, much larger than the native oxide, is present on top of each crystalline SiNW: in SiNWs with diameter below 10 nm, it takes the form of a silica NW of up to 50 nm in length. The new NW separates the initial catalyst particle into one that stays in contact with the SiNW and one or more that lies at the top of the new NW. The former is made of Cu and Cu3 Si and contains no Sn, whereas the latter keeps amounts of both elements. The observed microstructure appears to be the result of a mechanism of Si oxidation catalyzed by Cu3 Si. The deposit after SiNW growth, in the PECVD reactor, of a protecting 2 nm thick layer of hydrogenated amorphous Si, completely suppresses this mechanism. Reference for future applications based on Cu–Sn‐catalyzed quantum‐sized SiNWs is provided. Abstract : Quantum‐sized Si nanowires (NWs) are grown in a plasma‐enhanced chemical vapor deposition reactor by the vapor–liquid–solid method, using Cu–Sn bimetallic catalysts. Their exposure to ambient air creates a silica NW at their tip. The deposit after SiNW growth, of a protecting 1 nm thick layer of amorphous hydrogenated Si, completely suppresses this oxide NW.