Abstract
Anatase Nb-doped TiO_2 transparent conducting oxide has been formed on GaN(0001) surfaces using asputtering method.Amorphous films deposited at room temperature were annealed at a substrate temperature of 500℃ in vacuum to form single-phase anatase films.Films with a thickness of 170 nm exhibited a resistivity of 8×10^-4Ωcm with absorptance less than 5% at a wavelength of 460 nm.Furthermore,the refractive index of the Nb-doped TiO_2 was well matched to that of GaN. These findings indicate that Nb-doped TiO_2 is a promising material for use as transparent electrodes in GaN-based light emitting diodes(LEDs),particularly since reflection at the electrode/GaN boundary can be suppressed,enhancing the external quantum efficiency of blue LEDs.
