The role of metal layers in the formation of metal-silicon hybrid nanoneedle arrays

We investigated nanoneedle arrays fabricated on a series of metal-silicon substrates using Ga⁺ ion beam patterning. It is shown that the low sputtering rate of the metal is preserved on the tip of each nanoneedle in the form of a gallium alloy nanodot. The generated nanodot was found to greatly alleviate the ion sputtering of the underlying materials. These protective metals are promising materials that act as a shelter for the functional layer, which is vulnerable to ion beam irradiation. In the present work, as an example, we report a bundle of GaAs nanowhiskers that were successfully grown on each gold nanodot protected by an iron-gallium alloy.