Ultraviolet luminescence of Gd-doped a-SiXCYOZ:H films fabricated by plasma chemical vapor deposition

Thin a-SiXCYOZ:H films doped with gadolinium were prepared by plasma chemical vapor co-deposition (13.56 MHz) using hexamethyldisiloxane as a precursor of light-guide matrix, and tris(2,2,6,6-tetramethyl-3-5-heptanedionato)gadolinium(III) as a source of Gd3+ luminescent centers. The chemical structure of the films was investigated by X-ray photoelectron spectroscopy (XPS). We also performed measurements of optical absorption and photoluminescence. The Gd3+ emission at 312 nm was observed. It was found that the crucial role in this photoluminescence was played by the a-SiXCYOZ:H matrix in which Gd ions are surrounded by oxygen–silicon units (Gd3+–O–Si). The excitation of Gd3+ ions consists in a non-radiative transfer of energy absorbed in the matrix (200–230 nm) to the ions by a thermally activated process.