Browsing by Author "Lee, Yea-Chen"

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Enhanced Light Extraction in Wafer-Bonded AlGaInP-Based Light-Emitting Diodes via Micro- and Nanoscale Surface Textured
(2009-10-01)
Lee, Yea-Chen
;
Kuo, Hao-Chung
;
Cheng, Bo-Siao
;
Lee, Chia-En
;
Chiu, Ching-Hua
AlGaInP-based metal-bonding light-emitting diodes (LEDs) with micro- and nanoscale textured surface were investigated. The device surface with microbowls and nanorods were formed by a chemical wet-etching and dry-etching technique for enhancing light-extraction purpose. The luminous intensity could be enhanced 65.8% under 20-mA current injection as compared with the plane surface LEDs. The maximum wall-plug efficiency was achieved 14.1% at 7.5-mA operation.
Enhancement of flip-chip light-emitting diodes with omni-directional reflector and textured micropillar arrays (vol 19, pg 18, 2007)
(2007-09-01)
Lee, Chia-En
;
Lee, Yea-Chen
;
Kuo, Hao-Chung
;
Tsai, Meng-Ru
;
Cheng, B. S.
Enhancing the light extraction of (AlxGa1-x)(0.5)In0.5P-based light-emitting diode fabricated via geometric sapphire shaping
(2008-03-01)
Lee, Yea-Chen
;
Lee, Chia-En
;
Kuo, Hao-Chung
;
Lu, Tien-Chang
;
Wang, Shing-Chung
AlGaInP-based light-emitting diodes (LEDs) with a transparent sapphire substrate were fabricated by. the glue-bonding (GB) method. This transparent sapphire substrate is a geometric shaping structure by wet etching processes. Furthermore, the n-side-up surface has a nano-roughened texture by natural mask and chemical wet etching processes. The light output of this novel LED structure could be enhanced about 26.7% (at 350 mA) due to the higher light extraction as compared with the conventional GB-LEDs.
Further enhancement of nitride-based near-ultraviolet vertical-injection light-emitting diodes by adopting a roughened mesh-surface
(2008-05-01)
Lee, Chia-En
;
Lee, Yea-Chen
;
Kuo, Hao-Chung
;
Lu, Tien-Chang
;
Wang, Shing-Chung
In this letter, the nitride-based near-ultraviolet (NUV) vertical-injection light-emitting diodes (VLEDs) with roughened mesh-surface are proposed and demonstrated by a combination of pattern sapphire substrate, wafer bonding, laser lift-off, and chemical wet etching processes. With the help of adopting a roughened mesh-surface, the light-output power (at 350 mA) of the NUV-VLEDs could be further enhanced about 20% as compared with that of the conventional NUV-VLED.
High-brightness InGaN-GaN flip-chip light-emitting diodes with triple-light scatteriny layers
(2008-03-01)
Lee, Chia-En
;
Lee, Yea-Chen
;
Kuo, Hao-Chung
;
Lu, Tien-Chang
;
Wang, Shing-Chung
The flip-chip light-emitting diodes (FC-LEDs) with triple-light scattering layers were investigated comprising a top surface sapphire textured layer, an interface patterned sapphire layer, and a bottom naturally textured p-GaN layer. Such triple-textured layers are useful for light extraction efficiency enhancement. The light output power of FC-LEDs was increased 60% (at 350-mA current injection). compared to that of conventional FC-LEDs by implementing the triple-light scattering layers.
High-Performance (Al(x)Ga(1-x))(0.5)In(0.5)P-Based Flip-Chip Light-Emitting Diode With a Geometric Sapphire Shaping Structure
(2008-11-01)
Lee, Yea-Chen
;
Kuo, Hao-Chung
;
Lee, Chia-En
;
Lu, Tien-Chang
;
Wang, Shing-Chung
AlGaInP-based flip-chip light-emitting diodes (LEDs) with geometric sapphire shaping structures were fabricated by sapphire chemical etching and glue-bonded techniques. Furthermore, a nanoscale rough texture was applied on the epiwafer surface. This novel structure improved the output light power, wall-plug efficiency, and reliability. The output power of this structure was enhanced 31.2% under 350-mA current injection as compared with the conventional AlGaInP flip-chip LEDs.
High-Performance (AlxGa1-x)(0.5)In0.5P-Based Flip-Chip Light-Emitting Diode With a Geometric Sapphire Shaping Structure
(2008-11-01)
Lee, Yea-Chen
;
Kuo, Hao-Chung
;
Lee, Chia-En
;
Lu, Tien-Chang
;
Wang, Shing-Chung
AlGaInP-based flip-chip light-emitting diodes (LEDs) with geometric sapphire shaping structures were fabricated by sapphire chemical etching and glue-bonded techniques. Furthermore, a nanoscale rough texture was applied on the epiwafer surface. This novel structure improved the output light power, wall-plug efficiency, and reliability. The output power of this structure was enhanced 31.2% under 350-mA current injection as compared with the conventional AlGaInP flip-chip LEDs.
High-performance 650 nm resonant-cavity light-emitting diodes for plastic optical-fiber application
(2007-04-01)
Lee, Yea-Chen
;
Lee, Chia-En
;
Cheng, Bo-Siao
;
Lu, Tien-Chang
;
Kuo, Hao-Chung
AlGaInP-based resonant-cavity light-emitting diodes (RCLEDs) with high power and high speed have been fabricated. In this study, the RCLEDs were designed with different light-output aperture sizes 84, 60, and 40 pm, for different applications on plastic optical fibers. Small-signal modulation bandwidths as high as 3 10 MHz at a forward current of 20 mA and an output power as high as 1.5 mW can be achieved for devices with 40 pm apertures. The devices with 84 tm apertures had an output power of more than 3.5 mW at a driving current of 20 mA and a maximum efficiency of over 12% with an epoxy-encapsulated package. The devices with 40 mu m apertures satisfied with the IEEE 1394b s400 standard. Furthermore, the devices showed stable coupling efficiency for various currents and output powers at different ambience temperatures. In addition, the lifetime of devices is over 1300 h, and the power decay is less than 0.5 dB at 85 degrees C for a 40 mA driving current.
Nitride-Based Thin-Film Light-Emitting Diodes With Photonic Quasi-Crystal Surface
(2009-03-01)
Lee, Chia-En
;
Lai, Chun-Feng
;
Lee, Yea-Chen
;
Kuo, Hao-Chung
;
Lu, Tien-Chang
In this letter, the nitride-based thin-film light-emitting diodes (TFLEDs) with eight-fold photonic quasi-crystal (PQC) surfaces are proposed and demonstrated by a combination of wafer bonding, laser lift-off, and electron-beam lithography processes. By adopting a PQC surface, the light-output power (at 350 mA) of the PQC-TFLEDs exhibits 140% output power enhancement as compared with that of TFLEDs without a PQC surface.