AVS 56th International Symposium & Exhibition
    Applied Surface Science Tuesday Sessions
       Session AS-TuP

Paper AS-TuP19
Spectroscopic Ellipsometry of Bulk MAX-phases

Tuesday, November 10, 2009, 6:00 pm, Room Hall 3

Session: Applied Surface Science Poster Session
Presenter: A. Mendoza-Galvan, Cinvestav-Queretaro, Mexico
Authors: A. Mendoza-Galvan, Cinvestav-Queretaro, Mexico
M. Rybka, Linköping University, Sweden
K. Järrendahl, Linköping University, Sweden
H. Arwin, Linköping University, Sweden
M. Magnuson, Linköping University, Sweden
L. Hultman, Linköping University, Sweden
M. Barsoum, Drexel University
Correspondent: Click to Email
MAX-phases are compounds with the chemical formula Mn+1AXn where M is a transition metal, A is an element from column 13 to 16 in the periodic system and X represents C or N and n = 1, 2 or 3. These materials are potentially technologically important as they show unique refractory and other physical properties due to the combination of metals and ceramics. From a fundamental point of view the band structure of these materials are of interest and optical reference data are important to determine. Herein we report, for the first time, on the optical properties of NbTiAlC, Nb2AlC, TiSC2, Cr2GeC, TiGeC2, Ti2AlC, and Ti2AlN by spectroscopic ellipsometry in the 0.03 to 6.0 eV spectral range. The ellipsometric data in the infrared range show features corresponding to Fano modes indicating the presence of a thin oxide layer a few nm thick. The optical response of these MAX-phases is represented by a Drude-Lorentz model. Thus, in the low energy range the electrical conductivity through the Drude term is evaluated and two or three interband electronic transitions which are compositional dependent can be identified at photon energies in the visible-ultraviolet range 1.0-6.0 eV.