Growth of silicon and germanium nanowires in the vapour phase of high boiling point organic solvents

peer-reviewedHerein is presented the development of a versatile glassware based method for the growth of silicon and germanium nanowires. The vapour phase of a high boiling point solvent medium heated to reflux is used as a means of attaining the high temperatures required for the decomposition of organometallic precursors required for nanowire growth. Initially, the growth of self-catalyzed Ge nanowires on various noncatalytic substrates is presented in Chapter 3. This is followed in Chapter 4 by an in depth study of the various morphologies and defects seen within these Ge nanowires. A temperature related degree of nanowire kinking is presented and is rationalized in terms of changes in the nanowire growth directions. The growth of high density Ge nanowire mats from bulk Cu foil by a self-catalytic process without the need for defined catalyst particles is presented in Chapter 5. The nanowires were found to be catalyzed by an underlying in situ formed Cu3Ge layer which allowed excellent control over the nanowire diameters formed given the absence of discrete nanoparticle seeds. Further modification of the synthetic setup allowing the formation of Si nanowires directly on various substrates through catalysis by an evaporated In layer is presented in Chapter 6. Nanowire growth was achievable directly on stainless steel substrates which made the Si nanowires suited for use in Li ion cells. The method represents the first report of Si nanowire growth on substrates within an organic medium. Finally, the growth of Cu15Si4 nanowires on Cu foil using the same Si delivery system is presented in Chapter 7. The nanowires possess a tight diameter distribution and are the first nanowires of this Cu silicide phase formed to date