Plasmonic characteristics of niobium nitride thin films modulated by assisting ions

Abstract

NbNx films were prepared by dual ion beam sputter deposition. Different assisting ion current density Ja and assisting ion energy Ea were used to modulate the structural and dielectric properties of the films. All the films are of fcc structure, and assisting ions can improve their crystallinity. Higher Ja and Ea can reduce the screened plasma frequency and the optical energy loss of the films. Importantly, with appropriate experimental parameters, the NbNx films exhibit tunable dual epsilon-near-zero behavior. The assisting ions cause the variation of the carrier concentration in the films, and then modulate the dielectric properties of the films. Our results show that NbNx films can be applied in different fields by tailoring their plasmonic properties by assisting ions.