Enhancement of Yellow Light Extraction Efficiency of Y 3Al 5O 12:Ce 3+ Ceramic Converters Using a 2-D TiO 2 Hexagonal-Lattice Nanocylinder Photonic Crystal Layer

The effects of 2-D hexagonal-lattice TiO
₂
photonic crystal layers on the directional light extraction efficiency of low-scattering (Y
_1-x
Ce
_x
)
₃
Al
₅
O
₁₂
(YAG:Ce
³⁺
) ceramic converters have been investigated. The hexagonal-lattice TiO
₂
patterns were fabricated by an electron beam lithography process. The optimized yellow directional light extraction enhancement by a factor of 4.4 is achieved with a 2-D photonic crystal layer having a diameter of 430 nm, a lattice constant of 590 nm, and a height of 350 nm. A 3-D finite-difference time-domain model has also been developed to study the geometric parameters of the photonic crystal layer, yielding results that are consistent with our measured data.