We report the significant increase in the electrical conductivity, by five orders of magnitude, of Re-doped β-MoO3 epitaxial films grown using reactive DC magnetron sputtering. Re atoms were successfully incorporated into the films by using Mo-Re alloy targets, although the film compositions deviated significantly from those of the targets. Pristine β-MoO3 exhibited a conductivity below 10−7 S/cm, whereas β-Mo0.982Re0.018O3 exhibited a conductivity of 1.2 × 10−2 S/cm and a high optical transmittance of 67% (average) in the visible region. Furthermore, transparent conducting properties were reproduced in a polycrystalline film grown on a glass substrate, indicating the high potential of these films for use as transparent conductors.
