A Nb12O29 film is found to show transparent conducting properties with lowest resistivity of 3.3 × 10-3 Ω•cm at room temperature. High transmittance (∼70% at wavelength of 435 nm and ∼50% at wavelength of 730 nm, 120 nm in thickness) in the visible is maintained with an optical band gap of ∼4.0 eV. The optical dielectric constant and effective mass were both larger than those for conventional transparent conducting oxides, leading Nb12O 29 to exhibit high transparency. The n-type carrier density and Hall mobility at room temperature were 1.8 × 1021 cm-3 and 0.8 cm2 V-1s-1, respectively. The origin of the charge carriers lies in the mixed-valent character of Nb, as revealed by photoemission measurements. This intrinsically doped d-electron-based transparent conducting oxide shows unique characteristics such as high refractive index and high-temperature stability, that is, maintaining high conductivity after annealing at 1000 °C in vacuum.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films