Multifunctional Ti1-xTaxO2: Ta doping or alloying?

Useful electronic, magnetic, and optical properties have been proposed and observed in thin films of Ti_1-xM_xO₂ (M=Ta,Nb,V). In this work, we have studied phase formation for films of Ti_1-xTa_xO₂ prepared by pulsed laser deposition. We show that substitutional Ta in TiO₂ results in a different material system in terms of its electronic properties. Moss-Burstein shift is ruled out by comparing the electrical transport data of anatase and rutile TiO₂. Vegard's law fit to the blueshift data and the high energy optical reflectivity studies confirm the formation of an alloy with a distinct band structure. [ABSTRACT FROM AUTHOR]