Carbon doping of GaAs NWs

In this work we studied the carbon doping of gold-assisted GaAs nanowires. We show that carbon doping suppresses the migration of the gold nanoparticles from the tip of the nanowires and is accompanied by an increase of the axial growth rate and decrease of the lateral growth rate of the nanowires. These are attributed to the carbon adsorbates on the sidewalls of the nanowires. In addition, based on transmission electron microscopy analysis, we show that carbon doping eliminates the stacking fault formation. Raman scattering studies show that carbon doping has strong impacts on the longitudinal and transverse optical modes of the nanowires resulting in red-shifts and broadening of these modes. In addition, we observed the appearance of a forbidden mode which has been activated by the breakdown of the Raman selection rule. Raman studies confirm that the doped nanowires are free of stacking faults with zincblende crystal structure.