In-situ doping of erbium in hydrogenated amorphous carbon by low temperature metalorganic radio frequency plasma enhanced chemical vapor deposition

A significant improvement in the photoluminescence of erbium doped amorphous carbon (a-C:H(Er)) is reported. The effects of the RF power on the anode and cathode a-C:H films were investigated in terms of the microstructural and local bonding features. It was determined that Er doped a-C:H films should be placed on the anode to obtain wider bandgap and lower percentage of sp² carbon bonding. The metalorganic compound, tris(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate) Erbium(+ III) or Er(fod)₃, was incorporated in-situ into an a-C:H host by metalorganic rf plasma enhanced chemical vapor deposition. This technique provides the capability of doping Er in a vertically uniform profile. The high erbium concentration (3.9 at.%), partial fluorination of the surrounding ligands, and the large optical bandgap of the host a-C:H are the primary factors that enable enhancement of the photoluminescence. - Highlights: • High and uniform Er concentration (3.9 at.%) in a-C:H(Er) films is achieved. • Room-temperature photoluminescence peaking at 1.54 μm is demonstrated. • Optically active Er³⁺ ions are preserved in as-grown samples at low growth temperature. • Non-radiative C-H vibrational quenching is reduced by fluorination of a-C host. • Metalorganic-RF-PECVD provides the potential of doping Er in vertically uniform profiles