Vacuum ultra-violet spectroscopic ellipsometry study of single- and multi-phase nitride protective films

Abstract

This paper reports on a systematic investigation of the optical properties of Ta(1-x)Zr(x)N single-phase and ZrN-Ag multi-phase films fabricated by unbalanced magnetron sputtering using vacuum ultraviolet spectroscopic ellipsometry (VUV-SE). VUV-SE is a newly developed technique that was used to evaluate the strength and energy of the interband electronic excitations/transitions in these films. The energy of the interband transition was found to be altered by any changes in the elemental composition for single-phase materials. For example, it was found to increase with the increase in the covalent character of the bond as more Zr atoms are substituted for by Ta atoms in the ZrN rock-salt structure. In contrast, the peak positions did not vary in the multi-phase structures because the constituent phases were immiscible and retained their electronic structure. However, the strength and width of the interband transition were found to change to reflect changes in phase composition and microstructure. The optical and electronic properties of these materials were simulated using density functional theory (DFT) within the generalized gradient approximation. The calculated refractive indices and density of states were in good agreement with the VUV-SE data.

Functional properties of ceramic-Ag nanocomposite coatings produced by magnetron sputtering

“…An increase in the silver content produces well-defined diffraction patterns (SAED and XRD) indicating an FCC phase, evidencing an increment in the silver grain size when incorporated into crystalline (MeN [25,32,34,45,63,68,70,71,73,[75][76][77]106], MeO [14,49,105,[108][109][110]112]) or amorphous (C-based [28,96,103,104,121,125]) matrices. The silver grain size increment is accompanied by a decrease in the matrix grain size for crystalline matrices.…”

“…In ceramic-Ag films, SPR has been reported for a variety of matrices, with resonance bands ranging from 387 to 610 nm in wavelength [44][45][46][48][49][50][51]63,99,102], as detailed in Table 5. The nanoparticles' size distribution in the ceramic matrix determines the broadness or sharpness of the absorption peaks, and these differences can be attributed to the large distribution of silver particle sizes and shapes [44].…”

“…Thus, silver may promote the sliding of the grain boundaries more easily, reducing the hardness of the system. [1,2,18,27,30,32,35,37,45,64,69,71,77,78,106]. For hardness values reported in HK, a conversion factor was used to approximate the values in GPa (100 HK/GPa).…”

“…These coatings have attracted a considerable amount of attention due to their large range of applications. Their multi-phase character confers independent characteristics from each immiscible phase (ceramic or metallic) in the system, providing multiple functional properties, including antibacterial effects wear resistance [2,4,[23][24][25][26][27][28][29][30][31][32][33][34][35][36][37], corrosion resistance [18,29,[38][39][40][41][42] and light absorption enhancement [43][44][45][46][47][48][49][50][51][52], among others. One of the most interesting features of these materials is the possibility of tailoring their functionality by selecting the appropriate type, distribution and size of the constituent phases.…”

Spectroscopic ellipsometry for active nano- and meta-materials

“…Such compounds have been studied earlier by SE under the form of thin films [44][45][46][47][48][49][50], and recently, those displaying a Drude-like behavior have been shown to be of interest for plasmonic applications in the visible and near IR [51,52]. Note that in these recent works [51,52], the thin films were elaborated by pulsed laser deposition using conditions chosen to minimize optical losses detrimental to plasmonic applications (dense, homogeneous films with smooth surface).…”