Optical properties of low-energy Ag ion implanted monocrystalline silicon

Abstract

The present paper investigates the effects of low-energy silver ions implantation on the optical properties of monocrystalline silicon. Si(100) wafers were implanted with 60 keV Ag ions, to the fluences in the range of 1×1013-1×1016 ions/cm2. Composition of the implanted Si samples was analysed by means of Rurherford backscattering spectrometry and the optical spectra were obtained by spectroscopic ellipsometry measurements. The results revealed that the Ag ions are situated in the near-surface region of silicon, at depths of ~ 36 nm. When ion fluence of Ag ions was increased the concentration of Ag was also increased and for the highest ion fluence of 1×1016 ions/cm2 reach the value of ~ 6 at.%. At the fluence of 1×1014 ions/cm2 a strong apsorption in the optical spectra has been observed, which is associated with the excitation of surface plasmon resonance (SPR) of Ag nanoparticles. The position of the SPR peak shifted in the range of 326-1300 nm when the Ag ion fluence was varied up to 1×1016 ions/cm2. The results suggest that for higher implantation fluences the interaction between the Ag nanoparticles become important parameter which dominate the surface plasmon resonance effect of silver in Si.

Keywords

• SPR effect
• silicon
• silver nanoparticles
• ion implantation