Reduced electrical resistivity in TiO₂:Nb/ZnO:Ga film by thermal annealing

Abstract

Layered films consisting of transparent conducting oxides, Ga-doped ZnO (GZO) and Nb-doped TiO2 (TNO), were fabricated on glass substrates and their electrical properties were investigated. As-deposited TNO/GZO films showed the mean resistivity of TNO and GZO films. Thermal annealing reduced the resistivity of these films; however, TNO/GZO films exhibited the lowest value among them. The carrier concentration and Hall mobility of TNO/GZO films increased with the reduction in electrical resistivity. The thickness dependence, annealing temperature dependence, and crystalline orientation of the TNO and GZO layers in TNO/GZO films indicated that the improvement of the electrical properties of the GZO underlayer contributed to the resistivity reduction behavior of TNO/GZO films induced by thermal annealing.