Lattice location and electrical conductivity in Sb-implanted rutile

Single crystals of TiO2 (rutile) were implanted with Sb ions applying fluences of 2 x 10(13)/cm(2) to 5 x 10(16)/cm(2) 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 x 10(15)/cm(2) 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 sigma was observed with increasing Sb dose, indicating a saturation behavior at about 30 Omega(-1) cm(-1). Between 40 and 293 K 1n sigma was proportional to T--1/2 for low doses, and proportional to T--1/4 for doses of 1 x 10(16) Sb/cm(2) and above, indicating that the transport mechanism is due to variable range hopping.