On the dielectric constant of titanium dioxide

Abstract

Conductive rutile TiO2 has received considerable attention recently due to a number of applications. However, the static dielectric constant in conductive, reduced or doped TiO2 appears to cause controversy with reported values in the range 100-10000. In this work, we propose a method for measurements of the dielectric constant in conductive, n-type TiO2 that involves: (i) hydrogen implantation to form a donor profile at a known depth, and (ii) capacitance-voltage measurements for donor profiling. We can not confirm the claims stating an extremely high dielectric constant. On the contrary, the dielectric constant of conductive, reduced rutile TiO2 is similar to that of insulating rutile TiO2 established previously, with a Curie-Weiss type temperature dependence and the values in the range 160-240 along the c-axis.

Electrically-active defects in reduced and hydrogenated rutile TiO2

“…Capacitance-voltage (CV) measurements were carried out at room temperature using an Agilent 4284A LCR meter or a Boonton 7200 capacitance meter, respectively. The donor concentration, N d , was deduced from CV measurements, using the depletion approximation [38], a probing frequency of f meas = 1 MHz, and assuming a value of ϵ TiO2 = 160 at room temperature for the static relative dielectric constant of TiO 2 [39,40].…”

Green Synthesis of TiO2 Using Impatiens rothii Hook.f. Leaf Extract for Efficient Removal of Methylene Blue Dye

“…21,23 There are three crystallographic forms of TiO 2 , namely, anatase (tetragonal), rutile (tetragonal), and brookite (orthorhombic). 24,25 In general, TiO 2 is considered as an ecologically friendly and has been used in various industrial applications including gas sensors, 26 corrosion protection, 27 white pigment, 28 dye-sensitized solar cells, 29 remediation of the environment, 30 hydrogen gas production, 31 providing high dielectric constant and high electrical resistance, 32 and reduction of carbon dioxide. 33 Titanium dioxide NPs can be synthesized using a variety of methods, including sol−gel, sono-chemical, microwave-assisted, 34 deposition, hydro/solvothermal, and oxidation methods.…”

“…Due to its numerous benefits, such as great photocatalytic ability, high oxidizing power, low toxicity and biocompatibility, excellent chemical stability, and ease of accessibility, TiO 2 is one of the best materials for photocatalytic processes. , There are three crystallographic forms of TiO 2 , namely, anatase (tetragonal), rutile (tetragonal), and brookite (orthorhombic). , In general, TiO 2 is considered as an ecologically friendly and has been used in various industrial applications including gas sensors, corrosion protection, white pigment, dye-sensitized solar cells, remediation of the environment, hydrogen gas production, providing high dielectric constant and high electrical resistance, and reduction of carbon dioxide …”