Effect of N ion irradiation combined with thermal annealing on the optical absorption properties of Cu nanoparticles embedded in SiO2

Effect of the post N ion irradiation on Cu nanoparticles (NPs) has been investigated. The N irradiation at the fluences of 5 × 1015 and 1 × 1016 ions/cm2 give rise to different influences on surface plasmon resonance (SPR) of Cu NPs. Low fluence N ion irradiation can induce clear enhancement of the Cu SPR signal with a reduction of full width at half maximum (FWHM) after 600 °C annealing by tailoring the distribution of Cu NPs, while no obvious change of the Cu SPR signal is found in high fluence irradiated samples. The SPR peak becomes very weak after 800 °C annealing. The results from Rutherford back-scattering spectroscopy measurements give the evidence that with the increasing annealing temperature, the distribution of Cu content for all samples becomes narrower in SiO2 matrix. The Cu atoms can diffuse at high annealing temperature. The present study shows the interest of using N ion irradiation for modifying the optical properties of Cu NPs.