A gold nano-dot modified silicon tip apex for scanning Kelvin probe microscopy

In this paper, a gold nano-dot (Au-ND) is successfully prepared on a silicon tip apex for scanning Kelvin probe microscopy (SKPM) applications. An extra facile localized fluoride assisted Galvanic replacement reaction (LFAGRR) is proposed to replace the silicon (Si) atoms at the tip apex with Au ones. We successfully fabricated Au-ND coated tip apex by tapping the Si tip apex against a thin layer of electrolyte containing HAuCl₄ and HF, which is supported by a commercial anodic aluminum oxide (AAO) slice. In a typical process, a Au-ND with approximate 30 nm in diameter was fabricated within 30 seconds in the ambient condition. Our preliminary results demonstrated a cost-effective and facile process to prepare a noble metal-nanodot (metal-ND) modified AFM tip apex. It is expected that current technology has high potential to be applied to the applications of field sensitive scanning probe microscopy (FS-SPM).