A transparent metal: Nb-doped anatase TiO2

Abstract

This Letter focuses on the discovery of a transparent conducting oxide (TCO), anatase ${\mathrm{Ti}}_{1-x}{\mathrm{Nb}}_x{\mathrm{O}}_2$ films with $x=0.002–0.2$ . The resistivity of films with $x⩾0.03$ is $2–3\times {10}^{-4}\Omega \mathrm{cm}$ at room temperature. The carrier density of ${\mathrm{Ti}}_{1-x}{\mathrm{Nb}}_x{\mathrm{O}}_2$ can be controlled in a range of $1\times {10}^{19}\text{to}2\times {10}^{21}{\mathrm{cm}}^{-3}$ . The internal transmittance for films with $x⩽0.03$ ($40\mathrm{nm}$ thickness) is about 97% in the visible light region. The transport and optical parameters are comparable to those of typical TCOs, such as ${\mathrm{In}}_{2-x}{\mathrm{Sn}}_x{\mathrm{O}}_3$ and ZnO.