Sm-doped CdWO4 thin films synthesized by pulsed laser deposition

Samarium doped CdWO4 (Sm-CdWO4) thin films were synthesized by pulsed laser deposition (PLD) using pressed powder targets composed of Sm2O3, CdO, and WO3 mixtures. Congruent, stoichiometric, and crystalline thin films were obtained on glass substrates at 873 K using targets with 0.01 at. % Sm. The x-ray activated photoluminescence (x-ray PL) spectra were redshifted by about 40 nm at 298 K. Changes of the PL component at 2.85 eV into those at 2.20 and 2.52 eV were typical in their convolutions. These PL components showed very similar dependencies on excitation wavelengths, indicating that CdWO4 related PL emissions in the Sm-doped PLD films are relaxed from the same midband excited state. The PL peaks characteristic to Sm3+ had two sidebands shifted to both lower and higher energy sides as much as 0.03 eV. Plume emission spectra were analyzed to elucidate effects of Sm on our PLD processes. It was interpreted that energy transfer should occur between excited neutral Cd to the excited state of Sm3+ in laser plume. (C) 2001 American Institute of Physics.