For the purpose of development of highly energy-efficient light sources, one needs to design highly efficient green, red and yellow phosphors, which are able to absorb excitation energy and generate emissions. In this contribution, we present our results on producing some efficient phosphors with improved luminescence properties. The effects of zinc on the zinc-doped CaTiO3:Eu3+ phosphors have been investigated by varying the zinc concentrations. X-ray powder diffraction (XRD) and Scanning electron microscopy (SEM) characterizations were studies for their structural and morphological analysis. The variation of zinc concentration influences the crystallinity and morphology of the phosphors. The luminescence spectra of (Zn,Ca)TiO3: Eu3+ have been measured. Eu3+: (Zn,Ca)TiO3 have shown five emission transitions of 5D0→7F 0,1,2,3 & 4 located at 580 nm,593nm 615 nm,655 and 704 respectively with excitation at λexci=398nm (7F0→5L6). Moreover, the emitting phosphor developed in this study can be very effectively excited at the wavelengths of 398 nm. The (Zn, Ca)TiO3:Eu3+ can be used as a complementary phosphor in there red region for the white LEDs.

We studied physical properties of titanium hafnium oxide (TixHf1-xO2) alloy thin films deposited by pulsed DC reactive magnetron sputtering with AC substrate bias. Thin films of two end oxides, hafnium oxides (HfO2) and titanium oxides (TiO2), and their alloys TixHf1-xO2 with a range of compositions deposited with and without the substrate bias were compared to study the dependence of physical properties of the thin films on the substrate bias. Structural, chemical and optical properties of the thin films were analyzed to assess inter-relationship among these properties. Thin films deposited with the AC substrate bias consistently show much higher refractive index and significantly lower optical extinction coefficient than those of thin films deposited without the substrate bias suggesting that characteristic microstructures developed in these thin films are responsible for the differences in the optical properties.