Effect of ion dose and accelerating voltage during focused ion beam Si(111) surface treatment on GaAs nanowires growth

Experimental studies of the effect of dose and accelerating voltage during ion beam treatment of the Si(111) surface on the substrate structure and growth processes of GaAs nanowires have been carried out. For this purpose, arrays of areas were created on the Si(111) surface by ion beam treatment using an all-over template with variation of accelerating voltage in the range of 10–30 kV and dose in the range of 0.01–10.4 pC/µm2. Based on the results of the modified surface study after GaAs nanowire growth, the dependences of the main nanowire characteristics (density, length and diameter) on the ion beam dose were obtained. It is shown that the main influence on the formed nanowire characteristics is exerted by the dose of embedded Ga-ions. By changing the value of this ion beam parameter together with the high-temperature annealing, the chemical composition and morphology of the surface silicon oxide layer can be locally controlled, thereby predetermining the parameters of the growing nanowire array. In this case, the accelerating voltage, and, hence, the distribution of ions in the near-surface layer, is of secondary importance during all-over template processing. This is confirmed by the formation of identical nanowire arrays at different accelerating voltages since the growth of nanowires occurs under the same conditions on the Si surface after the annealing stage (as confirmed by Raman spectroscopy results).