Optical interband spectra and band structure of Ru2Si3 and Ru2Ge3.

Henrion W., Rebien M., Birdwell A. G., Antonov V. N., Jepsen O.

Hahn Meitner Inst Berlin Gmbh Dept Photovolta Kekulestr 5 D-12489 Berlin Germany
Univ Texas Dept Phys Richardson Tx 75083
Ukrainian Acad Sci Inst Met Phys Ua-252142 Kiev Ukraine
Max Planck Inst Festkorperforsch D-70569 Stuttgart Germany

Among the semiconducting silicides Ru2Si3 is considered to be an attractive material for optoelectronic and thermoelectric applications. However, only few papers on the electronic properties exist. Here we report results of optical investigations of this semiconducting material and its analogon Ru2Ge3 by spectroscopic ellipsometry in the spectral range of 0.7-10 eV and by UV-vis-near infrared (NIR) transmission and reflectivity measurements. The optical spectra for Ru2Si3 and Ru2Ge3 exhibit semiconducting character with dominant interband features around 2 and 5 eV and a relative minimum in the joint density of interband states between 3 and 4 eV. More pronounced structures were found for single crystalline samples than for solid phase crystallized thin films. The dielectric functions are compared with theoretical calculations of the optical properties which have been carried out using the LMTO-ASA method. Good agreement has been found between theory and experiment for the spectral distribution of optical constants.

Thin Solid Films, 364 171-176, 2000.

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