Nsg30 probes

Fe nanoparticles were formed via the solid-state dewetting method on a hard sapphire substrate. Fe film of 25 nm in thickness was deposited with the aid of magnetron sputtering on the 0.43 mm thick (0001)-oriented polished sapphire single crystal substrates that was ultrasonically cleaned with acetone, ethanol and de-ionized water before deposition. The deposition was performed with RF Magnetron sputtering tool, supplied by “von Ardenne”, using 99.9% pure Fe target by “Kurt J. Lesker” Company. The base pressure in the system and the Ar sputtering pressure were 3 × 10⁻⁷ Torr and 3 × 10⁻⁷ Torr, respectively. The thermal treatment at 850 °C for 24 h was performed in tube furnace in the flow of Ar + 10%H₂ ultra-high purity gas, to prevent the oxidation and to cause a reduction of thin surface oxide film formed during samples manipulation in air. The samples were placed in the quartz boat and introduced into the hot zone of the furnace by a manipulator. The particles were characterized by Atomic Force Microscope (AFM) (XE – 70, Park Systems Corp.) operating in the tapping mode (NSG30 probes by NT-MDT). All nanoparticles had a faceted shape with a {110} upper facet parallel to the interface. TEM analysis revealed a thin, ~5 nm-thick hydroxide layer on the surface of the nanoparticles (Fig. S1 in the Supplemental Information).