Influence of anatase-rutile phase transformation on dielectric properties of sol-gel derived TiO2 thin films

Abstract

The phase transformation behavior and resulting dielectric properties of sol-gel derived TiO 2 thin films were investigated. Thin films showed a typical behavior of mixture systems during the phase transformation; a kinetic investigation on the isothermal curve of pre-crystallized thin films revealed that the phase transformation was a first-order reaction with an Avrami time component of 1. Dielectric constants of TiO 2 thin films increased with the increasing amount of the rutile phase while the dielectric losses showed the opposite relationship. From a fitting process using the parallel mixing rule, dielectric constants of two end members of the mixture system were calculated to be 41.4 and 145.2 for the pure anatase and rutile phase thin films, respectively.

The substrate temperature dependent electrical properties of titanium dioxide thin films

“…For samples deposited at T s = 581 K, which contain anatase phase in proportion of 56%, the calculated dielectric constant (e) can be taken as about 80 [14]. For other, 100% anatase phase sample which is deposited at T s = 523 K, e is about 41.4 [14].…”

Electrical relaxation dynamics in TiO2 – polymer matrix composites

“…TiO 2 is dielectrically anisotropic material, its unit cell attains tetragonal crystal structure and the static values of dielectric permittivity in the perpendicular and the lateral direction differ significantly [20]. Titanium oxide is classified as a polar oxide, exhibiting transitions between crystal structures with varying symmetry [21]. The local environment of the titanium sites in rutile is similar to that in barium titanate.…”

Enhanced photoactive and photoelectrochemical properties of TiO2 sol–gel coated steel by the application of SiO2 intermediate layer

“…Groner and George [54] acknowledge that TiO 2 is characterized by dielectric constant values ranging from 50 to 110 and, within that range, rutile phase exhibits higher values than anatase phase. Furthermore, according to Kim et al the dielectric constants are 41.3 and 145.2 for the pure anatase and rutile thin films, respectively [55]. Nevertheless, although the exact value is correlated to the references quoted and may also slightly depend on the used manufacturing method, it is evident that dielectric constant for anatase TiO 2 is much higher than that for SiO 2 .…”