Tunable plasmonic properties of silver nanoparticles embedded in amorphous-carbon ultrathin films deposited by co-sputtering

In the present work, silver nanoparticle embedded in amorphous-carbon (Ag:a-C) ultrathin films of different thicknesses ∼2-30 nm have been grown on the glass substrate at room-temperature using DC/RF magnetron co-sputtering. The structural and composition properties of Ag:a-C ultrathin films were investigated by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX), which confirm the formation of crystalline Ag nanoparticles embedded in a-C matrix. It also indicates that nanoparticle size and atomic% of Ag increased by increasing film thickness. The morphology and thickness of the samples were demonstrated by scanning electron microscope (SEM). The plasmonic properties of Ag:a-C were investigated by transmittance spectra using UV-Vis-NIR spectrophotometry and correlated with the structural properties as a function of varying thickness (∼2-30 nm). The transmittance spectra revealed the tuneable localized surface-plasmon resonance (LSPR) wavelength from ∼488 nm to 445 nm (blue-shift) by increasing the thickness of Ag:a-C ultrathin film. This new study on plasmonic properties of Ag:a-C ultrathin films is expected to have a significant impact on the development of advanced flexible photonic and optoelectronic devices.