Lattice location and electrical conductivity in Sb-implanted rutile

Single crystals of TiO₂ (rutile) were implanted with Sb ions applying fluences of 2×{}10¹³/cm² to 5×{}10¹⁶/cm² at 300 keV. The lattice location together with the ion range and damage distribution was measured using Rutherford-backscattering and channeling. The conductivity was measured as a function of temperature in the region between 6 and 300 K. Up to a dose of 5×{}10¹⁵/cm² the Sb atoms were entirely substitutional on Ti sites as concluded from channeling measurements on 〈001〉- and 〈100〉-oriented TiO₂ single crystals. A large increase of the conductivity {σ} was observed with increasing Sb dose, indicating a saturation behavior at about 30 Ω^-1{cm}^{{{-}}1}. Between 40 and 293 K ln σ was proportional to{T}^{{{-}}1/2}$ for low doses, and proportional to ${T}^{{{-}}1/4}for doses of 1×{10}¹⁶$ Sb/${cm}²$ and above, indicating that the transport mechanism is due to variable range hopping.