Fabrication and luminescence properties in Yb –Tb co-doped a-SiCO thin films

Amorphous silicon oxycarbide (a-SiCxOy) single doped with Yb and co-doped with the couple Tb Yb thin films were grown on crystalline silicon substrates by rf magnetron sputtering. The elemental composition in at. % is determined by energy dispersive spectroscopy and fourier transform infrared spectroscopy allows to investigate the chemical properties of the host. The concentration of Yb in the single doped sample was 3.5% and for the codoped samples (Yb, Tb) were (3%, 0.9%), (3.5%, 0.6%) and (4%, 0.6%), respectively. Post-deposition annealing treatments were made in order to induce optical activation of the rare earths. Conversion or absorption of high energy photons were analyzed by photoluminescence spectroscopy. The photoluminescence spectra show that for a given temperature range in the thermal annealing process, as well as for the appropriate rare earth concentrations the activation of Yb and Tb is enhanced. A strong reduction of the Tb emission in contrast to the Yb emission in the a-SiCxOy,:Tb:Yb samples at annealing temperature at 500°C suggests a energy transfer from Tb to Yb ions. Copyright © 2018 VBRI Press.