Abstract
Polycrystalline plate-like TiO2 specimens were irradiated with a continuous-wave Yb-fiber laser, and the electrical properties of the modified layers were investigated. The irradiated part was modified in color and electrical properties when the laser power was set above a certain threshold. The color changed from white to black, and the electrical resistivity drastically decreased from an initial value of 3.3 × 109 Ω cm to 1.9 Ω cm at 2.0 W. The Hall measurement showed that the modified layer was an n-type semiconductor, and the carrier concentration was 3.6 × 1017 cm−3 at 2.0 W.