Browsing by Author "Ku, Chun-Han"

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Improvement of light extraction for AlGaN-based near UV LEDs with flip-chip bonding fabricated on grooved sapphire substrate using laser ablation
(2019-06-01)
Ku, Chun-Han
;
Wang, Wei-Kai
;
Horng, Ray-Hua
;
交大名義發表
;
電子工程學系及電子研究所
Mesh-textured flip-chip (FC) structures of AlGaN-based near ultraviolet-light-emitting diodes (NUV-LEDs) are fabricated using an Nd:YAG laser scriber. Compared with the output power of the reference FC-LEDs, those of conventional sapphire substrate (CSS) FC-LEDs and the patterned sapphire substrate FC-LEDs with laser-scribed mesh-textured backsides were improved by 28.7% and 7.2%, respectively. The CSS FC-LED is enhanced using the mesh-textured trench pattern attributable to an increase in the light-extraction efficiency resulting from an increase in the photon-escape probability due to enhanced light scattering at the trench-patterned-sapphire/air interface. Furthermore, the current-voltage curves depict that the laser scribing process does not adversely affect the electrical properties of the FC-LEDs. A Trace-Pro simulation revealed that the laser-scribed-trench CSS FC-LED is effective for light extraction.