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

paper

Temperature dependent optical studies of Ti $_{1 - x}$ Co $_{x}$ O $_{2}$

arXiv:cond-mat/0303177 · doi:10.1063/1.1619212

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.

8 pages, 4 figures

Temperature dependent optical studies of Ti1−x​Cox​O2​

Abstract

Temperature dependent optical studies of Ti $_{1 - x}$ Co $_{x}$ O $_{2}$