Kovalev, A. I. , Rashkovskiy, A. Yu , Wainstein, D. L. , Gago, R. , Soldera, F. , ENDRINO ARMENTEROS, JOSÉ LUIS
Si
Curr. Appl. Phys.
Article
Científica
1.971
0.655
01/04/2016
000370699200006
2-s2.0-84957562805
TiAlN/Ag multilayer coatings with different number of bilayers and thicknesses of individual layer were fabricated by DC magnetron sputtering. Thermal conductivity and electronic structure features were measured on a set of samples with different number of bilayers and individual layer thickness from a 5 -150 nm for total coating thickness of similar to 0.5 or 1 mu m. It was found that thermal conductivity of the multilayer insulator/metal structure becomes lower than for monolithic TiAlN coatings with the same thickness when Ag layers are thinner than 25 nm. The physical nature of thermal barrier properties of the nanolaminate TiAlN/Ag films is studied using X-ray photoelectrons (XPS) and high-resolution electron-energy loss (HREELS) spectroscopies. Based on these results, a physical model for the anomalous decrease in heat conductivity for nanoscale multilayers was developed on base of analysis of plasmon and lattice vibrations inside the layers and at the interfaces. Anomalously low heat transfer is attributed to attenuation of longitudinal acoustic phonons vibrations, decreasing of plasmon-polariton penetration on interfaces, and plasmon states splitting in Ag nanolayers due to confinement effects at multilayer coatings nanostructuring. (C) 2016 Elsevier B.V. All rights reserved.
TiAlN/Ag multilayers; Electronic structure; Phonons; Plasmon-polariton penetration; Ag nanolayers