Chemical vapor deposition route to transparent thick films of Eu<sup>3+</sup>-doped HfO<sub>2</sub> and Lu<sub>2</sub>O<sub>3</sub> for luminescent phosphors
Shogen Matsumoto, Akihiko Ito
Abstract
Crystal growth from the vapor phase is an alternative to melt solidification and sintering for fabricating optical materials with high melting points and reversible phase transformations. We demonstrated the rapid synthesis of transparent thick films of Eu-doped monoclinic HfO 2 (Eu 3+ :HfO 2 ) and cubic Lu 2 O 3 (Eu 3+ :Lu 2 O 3 ) using laser-assisted metal–organic chemical vapor deposition. The transparent single-crystalline films were epitaxially grown on yttria-stabilized zirconia substrates at the deposition rates of 15–20 µm h −1 . Under irradiation by ultraviolet light, the Eu 3+ :HfO 2 and Eu 3+ :Lu 2 O 3 transparent thick films exhibited intense red emissions at 614–615 nm corresponding to the 5 D 0 → 7 F 2 transitions of the Eu 3+ ions located in asymmetric environments.