Temperature dependent optical studies of Ti$_{1-x}$Co$_x$O$_2$

S. Guha; K. Ghosh; J. G. Keeth; S. B. Ogale; S. R. Shinde; J. R. Simpson; H. D. Drew; T. Venkatesan

doi:10.1063/1.1619212

Temperature dependent optical studies of Ti$_{1-x}$Co$_x$O$_2$

Materials Science 2009-11-10 v1

Authors: S. Guha , K. Ghosh , J. G. Keeth , S. B. Ogale , S. R. Shinde , J. R. Simpson , H. D. Drew , T. Venkatesan

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Abstract

We present the results of Raman and photoluminescence (PL) studies on epitaxial anatase phase Ti $_{1-x}$ Co $_x$ O $_2$ films for $x$ = 0-0.07, grown by pulsed laser deposition. The low doped system ( $x$ =0.01 and 0.02) shows a Curie temperature of ~700 K in the as-grown state. The Raman spectra from the doped and undoped films confirm their anatase phase. The photoluminescence spectrum is characterized by a broad emission from self-trapped excitons (STE) at 2.3 eV at temperatures below 120 K. This peak is characteristic of the anatase-phase TiO $_2$ and shows a small blueshift with increasing doping concentration. In addition to the emission from STE, the Co-doped samples show two emission lines at 2.77 eV and 2.94 eV that are absent in the undoped film indicative of a spin-flip energy.

Keywords

Raman spectroscopy photoluminescence TiO$_2$ Co-doping Curie temperature self-trapped excitons

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@article{arxiv.cond-mat/0303177,
  title  = {Temperature dependent optical studies of Ti$_{1-x}$Co$_x$O$_2$},
  author = {S. Guha and K. Ghosh and J. G. Keeth and S. B. Ogale and S. R. Shinde and J. R. Simpson and H. D. Drew and T. Venkatesan},
  journal= {arXiv preprint arXiv:cond-mat/0303177},
  year   = {2009}
}

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8 pages, 4 figures

Temperature dependent optical studies of Ti$_{1-x}$Co$_x$O$_2$

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