Er-, Nd- and Tm-doped Si-yttria stabilized zirconia (YSZ) thin film samples
were prepared by rf co-sputtering. Chemical composition of the samples was
determined using energy-dispersive spectroscopy (EDS) and the structure
of the films by x-ray diffraction (XRD). The samples were annealed to
700 °C. Photoluminescence (PL) measurements were performed for the visible and infrared.
Excitation with 457.9 nm produces spectra in the visible range due mostly to defects in the
YSZ matrix with a weak Si nanoparticle surface state emission; the Tm-doped samples also
present emission. Excitation with 488 nm produces spectra in the visible range with additional
rare earth emissions such as the and emissions for the Er-doped samples and the emissions for the Nd-doped samples. The Er-doped samples present weak emissions and narrow emissions in the infrared range, while the Nd-doped samples present and emissions. No Tm3+
emissions in the infrared were observed. Excitation wavelength dependence measurements
for the emissions show that these are due to energy transfer from the defects in the YSZ as
well as from the Si nanoparticles while the same measurements for the emissions show that these are due to energy transfer from the Si nanoparticles only.
Excitation flux dependence measurements for the and emissions show the sub-linear dependence characteristic of rare earth ion excitation
through energy transfer from Si nanoparticles. emission dependence on emission showed that the former was possibly due to a combination of downconversion
from higher levels of the Er ions, energy transfer from Si nanoparticles and upconversion
transfer processes.
We concluded that Er-, Nd- and Tm-doped Si-YSZ are promising materials for photonic
applications, being easily broadband excited using low pumping powers.