Formation of mono-layered gold nanoparticles in shallow depth of SiO2 thin film by low-energy negative-ion implantation

Abstract

Mono-layered gold nanoparticles just below the surface of silicon oxide film have been formed by a gold negative-ion implantation at a very low-energy, where the deviation of implanted atoms was sufficiently narrow comparing to the size of nanoparticles. Gold negative ions were implanted into SiO2 thin films on Si substrate at energies of 35, 15 and 1keV. The samples were annealed in Ar flow for 1h at 900 or 1000°C. Cross-sectional TEM observation for the implantation at 1keV showed existence of Au nanoparticles aligned in the same depth of 5nm from the surface. The nanoparticles had almost same diameter of 7nm. The nanoparticles were found to be gold single crystal from a high-resolution TEM image.