Hydrated magnesium-carbon films with conductivity and wide-range visible-to-far-infrared transparency

The hydrated magnesium-carbon films fabricated in this study are the novel-innovative non-oxide-type transparent electronic material. The films, which have a structure similar to that of magnesium hydroxide, were produced by making Mg_x-C_y films deposited by magnetron co-sputtering react with water vapor. As the extrinsic defect of hydration magnesium-carbon films, C atoms provided redundant electrons, resulting in a conductivity of approximately 3.31 × 10⁻² Ω·cm. Although the conductivity of hydrated magnesium-carbon films is not prominent comparing to the conventional and widely-used n-type TCO materials, e.g. ITO, the films also showed excellent optical properties, which can be attributed to their low bond energy, with the infrared transmittance of the films being greater than 72% for a plasma wavelength of approximately 10 μm. By varying the atomic C content of the films, a visible-region transmittance greater than 80% could be realized. The optical bandgap of the films was approximately 4.04–6.87 eV and was blue-shifted because of the Moss-Burstein effect.