Catalyst-free synthesis of silicon nanowires by oxidation and reduction process
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A new process has been developed to grow silicon (Si) nanowires (NWs), and their growth mechanisms were explored and discussed. In this process, SiNWs were synthesized by simply oxidizing and then reducing Si wafers in a high temperature furnace. The process involves H2, in an inert atmosphere, reacts with thermally grown SiO2 on Si at 1100 °C enhancing the growth of SiNWs directly on Si wafers. High-resolution transmission electron microscopy studies show that the NWs consists of a crystalline core of ~25 nm in diameter and an amorphous oxide shell of ~2 nm in thickness, which was also supported by selected area electron diffraction patterns. The NWs synthesized exhibit a high aspect ratio of ~167 and room temperature phonon confinement effect. This simple and economical process to synthesize crystalline SiNWs opens up a new way for large scale applications.
This work was supported by Foreign Affairs and International Trade Canada (DFAIT) under Commonwealth Graduate Student Exchange Program Scholarship (2011–2012). Q.Y. and A.H. acknowledge the support from NSERC and Canada Research Chair Program. S.K.B. and Q.Y. acknowledge the technical assistance from Dave McColl, Plasma Physics Laboratory, Rob Peace, Department of Mechanical Engineering and Jason Maley, SSSC, University of Saskatchewan, Canada. S.K.B. and O.J. acknowledges Prof. T. Harinarayana, Director, GERMI Research, Innovation and Incubation Centre, India. The EM research described in this paper was performed at the Canadian Centre for Electron Microscopy at McMaster University, which is supported by NSERC and other government agencies.