Clustering of gold particles in Au implanted CrN thin films: The effect on the SPR peak position

Abstract

We report on the formation of gold particles in 280 nm thin polycrystalline CrN layers caused by Au+ ion implantation. The CrN layers were deposited at 150 degrees C by d.c. reactive sputtering on Si(100) wafers and then implanted at room temperature with 1501keV Au+ ions to fluences of 2 x 10(16) cm(-2) to 4.1 x 10(16) cm(-2). The implanted layers were analysed by the means of Rutherford backscattering spectrometry, X-ray diffraction, atomic force microscopy and spectroscopic ellipsometry measurements. The results revealed that the Au atoms are situated in the near-surface region of the implanted CrN layers. At the fluence of 2 x 10(16) cm(-2) the formation of Au particles of similar to 200 nm in diameter has been observed. With increasing Au ion fluence the particles coalesce into clusters with dimensions of similar to 7 mu m . The synthesized particles show a strong absorption peak associated with the excitation of surface plasmon resonances (SPR). The position of the SPR peak shifted in the range of 426.8-690.5 nm when the Au+ ion fluence was varied from 2 x 10(16) cm(-2) to 4.1 x 10(16) cm(-2). A correlation of the shift in the peak wavelength caused by the change in the particles size and clustering has been revealed, suggesting that the interaction between Au particles dominate the surface plasmon resonance effect. (C) 2017 Elsevier B.V. All rights reserved.