Conductivity of TiO2 nanotubes: Influence of annealing time and temperature

► Ordered TiO2 nanotube layers of different tube-length were grown by anodic self-organization and their conductivity characterized. ► Under appropriate annealing conditions amorphous tubes are converted to anatase or rutile which affects their conductivity drastically. ► Anatase tubes show significantly higher conductivity than rutile containing tubes. ► Tube length increase leads not only to an (expected) increase in the resistivity but also increases the specific resistivity of the tube layer.