Gold nanoparticle fabrication in single crystal SiO2 by MeV Au ion implantation and subsequent thermal annealing

Abstract

Gold nanoparticles were fabricated by ion implantation and subsequent high temperature annealing. 3.0 Mev Au+ ions were implanted into single crystalline c-plane (0001) hexagonal SiO2 at fluences below the threshold for spontaneous cluster formation, from 1014 ions/cm2 to 2×1016 ions/cm2. The dose dependence, high temperature annealing effect and optical properties were studied. The typical optical absorption band of 520 nm is not found prior to heat treatment for all implanted samples. By sequential heat treatment at different temperatures, we have found that the optical absorption is critically dependent on annealing temperature. After annealing at 1000°C for 5 h, the samples implanted at fluences above 1×1016 ions/cm2 display optical absorption bands peaked at 2.37 eV (523 nm) which is characteristic of surface plasmon resonance of gold nanoparticles. The average particle radius of Au colloid particles is estimated to be about 4.2 nm. RBS/Channeling analyses show the implanted Au to have the Gaussian profiles both before and after sequential annealing at different temperatures, and that the ion range is in a good agreement with the prediction from TRIM calculation.