Using ion beams to tune the nanostructure and optical response of co-deposited Ag : BN thin films

Abstract

The present study is devoted to co-deposited Ag : BN nanocermet thin films and is focused on the influence of ion irradiation conditions on their structural and linear optical properties. Ion irradiation was performed in situ during the growth of the nanocermets using a 50 eV assistance beam (nitrogen/argon or nitrogen-ion assistance) and ex situ on as-grown films using a 120 keV argon-ion beam (post-irradiation). Grazing incidence small-angle x-ray scattering measurements show that (i) as-grown N-assisted films contain prolate spheroidal clusters (height-to-diameter ratio H/D ≈ 1.8), (ii) N/Ar-ion assistance leads to the formation of more elongated clusters (H/D ≈ 2.1) and (iii) post-irradiation leads to a decrease of H/D to a value close to 1. These results are discussed on the basis of atomic diffusion processes involved during the growth of the nanocermets and during the post-irradiation. The optical transmittance spectra of these films measured at normal incidence display one absorption band, due to the excitation of the (1,1) plasmon mode of the clusters. In the case of the as-grown films, an additional band appears at oblique incidence for P-polarized light, as a consequence of the excitation of the (1,0) plasmon mode of the clusters. Our results show that the spectral position of the absorption bands (which can be tuned in the 400-600 nm range) depends on the H/D ratio of the clusters, in good agreement with calculations of optical transmittance considering the nanocomposite layer as a uniaxial anisotropic medium whose dielectric tensor is described by an anisotropic Maxwell-Garnett model.

Advanced optical effective medium modeling for a single layer of polydisperse ellipsoidal nanoparticles embedded in a homogeneous dielectric medium: Surface plasmon resonances

“…In this small-size limit, it is usually claimed that a heterogeneous nanocomposite material can be considered as a homogeneous medium whose macroscopic optical response is described by an effective dielectric tensor. Effective medium theories were developed for a 3D [31][32][33][34][35] or a 2D organization 36,37 of the NPs. In the frequently encountered case of single layers of NPs (2D organization), the simplest method was proposed by Yamaguchi et al three decades ago.…”

Spectrally Tailored Light‐Matter Interaction in Lithography‐Free Functional Nanomaterials

“…TiN was pointed as a low‐cost alternative metal to Au with comparable visible and near‐infrared plasmonic properties and a better stability for high‐temperature applications . TiN nanoparticles with a controlled morphology can be grown and self‐assembled with techniques such as sputtering deposition in a similar way as noble metals . A remarkable achievement enabled by a skilled use of these techniques is the fabrication of “black TiN” as shown in Figure .…”

“…[22] TiN nanoparticles with a controlled morphology can be grown and self-assembled with techniques such as sputtering deposition in a similar way as noble metals. [6,[23][24][25] A remarkable achievement enabled by a skilled use of these techniques is the The scattering pattern (seen in (a)) resulting from the excitation of multiple SPPs by the incident beam at normal incidence (seen also in (a)) is representative of the wavelength and polarization of this beam. Reproduced with permission.…”

Structure, stability and mechanical performance of AlN:Ag nanocomposite films

“…bond strength), a strong effect is also imposed by deformation mechanisms such as generation and movement of dislocations and/or grain boundaries. At the same time, the dielectric character of AlN in combination with the metallic nanoparticles may add extra functionalities to these coatings [9,10]. However, the growth of such AlN-noble metal nanocomposites has not been reported yet in the literature, possibly due to the miscibility of Al into noble metals [11,12] making the Ag-AlN phase separation and the formation of nanocomposites a very difficult task; similar alloying has been also observed in Ag-Ga-N systems [13].…”