It was shown that the morphology of gold-assisted GaAs nanowires could be strongly modified by the presence of CBr4 vapour during growth by metal-organic vapour phase epitaxy. GaAs nanowires were grown under conditions which result in strong tapering and lateral growth at low growth temperatures by the use of triethylgallium instead of the more usual precursor, trimethylgallium. Under these conditions, nanowires grown in the presence of CBr4 exhibit higher axial and lower radial growth rates, and negligible tapering compared with nanowires grown in the absence of CBr4 under the same conditions. This was attributed primarily to the suppression of the 2d growth rate by CBr4, which enhanced the axial growth rate of the nanowires. Nanowires grown with CBr4 had a stacking-fault-free zincblende structure, while the nanowires grown without CBr4 contained a high density of stacking faults. This work emphasized the striking effects which precursor chemistry could have upon nanowire morphology.

Effect of Carbon Tetrabromide on the Morphology of GaAs Nanowires. O.Salehzadeh, S.P.Watkins: Nanotechnology, 2011, 22[16], 165603