Optical and electronic properties of conductive ternary nitrides with rare- or alkaline-earth elements

Conductive nitrides, such as TiN, are key engineering materials for electronics, photonics, and plasmonics; one of the essential issues for such applications is the ability of tuning theconduction electron density, theresistivity, and theelectron scattering. While enhancing theconduction electron density and blueshifting the intraband absorption towards the UV were easily achieved previously, reducing theconduction electron density and redshifting the intraband absorption into the infrared are still an open issue. The latter is achieved in this work by alloying TiN by rare earth (RE  = Sc, Y, La) or alkaline earth (AE = Mg, Ca) atoms in Ti substitutional positions. The produced TixRE1 −xN and TixAE1 −xN thin film samples were grown by a hybrid arc evaporation/sputtering process, and most of them are stable in the B1 cubic structure. Their optical properties were studied in an extensivespectral range by spectroscopic ellipsometry. The ellipsometricspectra were analyzed and quantified by the Drude-Lorentz model, which provided theconduction electron density, the electron mean free path, and theresistivity. The observed interband transitions are firmly assigned, and the optical and electrical properties of TixRE1 −xN and TixAE1 −xN are quantitatively correlated with their composition and crystal structure.

Source: Journal of Applied Physics - December 8, 2016 Category: Physics Authors: S. Kassavetis, A. Hodroj, C. Metaxa, S. Logothetidis, J. F. Pierson and P. Patsalas Source Type: research