A transparent metal: Nb-doped anatase TiO2

TLDR

This Letter reports the discovery of a transparent conducting oxide, anatase Ti1−xNbxO2 films with x ranging from 0.002 to 0.2. The carrier density in Ti1−xNbxO2 can be tuned from 1×10^19 to 2×10^21 cm−3. Ti1−xNbxO2 films with x≥0.03 exhibit low resistivity (2–3×10−4 Ω cm) and, for x≤0.03, maintain ~97 % visible transmittance, matching the transport and optical performance of standard TCOs such as In2−xSnxO3 and ZnO.

Abstract

This Letter focuses on the discovery of a transparent conducting oxide (TCO), anatase Ti1−xNbxO2 films with x=0.002–0.2. The resistivity of films with x⩾0.03 is 2–3×10−4Ωcm at room temperature. The carrier density of Ti1−xNbxO2 can be controlled in a range of 1×1019to2×1021cm−3. The internal transmittance for films with x⩽0.03 (40nm thickness) is about 97% in the visible light region. The transport and optical parameters are comparable to those of typical TCOs, such as In2−xSnxO3 and ZnO.