On the permittivity of titanium dioxide

Conductive rutile TiO(2) has received considerable attention recently due to multiple applications. However, the permittivity in conductive, reduced or doped TiO(2) appears to cause controversy with reported values in the range 100–10,000. In this work, we propose a method for measurements of the permittivity in conductive, n-type TiO(2) that involves: (i) hydrogen ion-implantation to form a donor concentration peak at a known depth, and (ii) capacitance–voltage measurements for donor profiling. We cannot confirm the claims stating an extremely high permittivity of single crystalline TiO(2). On the contrary, the permittivity of conductive, reduced single crystalline TiO(2) is similar to that of insulating TiO(2) established previously, with a Curie–Weiss type temperature dependence and the values in the range 160–240 along with the c-axis.