🏛️國立陽明交通大學機構典藏

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Light-output enhancement in a nitride-based light-emitting diode with 22 degrees undercut sidewalls
(2005-01-01)
Kao, CC
;
Kuo, HC
;
Huang, HW
;
Chu, JT
;
Peng, YC
We successfully fabricated nitride-based light-emitting diodes (LEDs) with similar to 22degrees undercut sidewalls. The similar to 22degrees etching undercut sidewalls were achieved by controllable inductively coupled plasma reactive ion etching. With a 20-mA current injection, the output powers of the LED with similar to 22degrees undercut sidewalls and standard LED were 5.1 and 3 mW, respectively-a factor of 1.7 times enhancement. It was found that such undercut sidewalls could enhance the probability of escaping the photons outside from the LED in the near horizontal and in-plane directions. This simple and controllable method is beneficial to fabricate brighter LEDs.
Improvement of InGaN-GaN light-emitting diode performance with a nano-roughened p-GaN surface
(2005-05-01)
Huang, HW
;
Kao, CC
;
Chu, JI
;
Kuo, HC
;
Wang, SC
This investigation describes the development of InGaN-GaN light-emitting diode (LED) with a nano-roughened top p-GaN surface which uses Ni nano-mask and wet etching. The light output of the InGaN-GaN LED with a nano-roughened top p-GaN surface is 1.4 times that of a conventional LED, and wall-plug efficiency is 45% higher. The operating voltage of InGaN-GaN LED was reduced from 3.65 to 3.5 V at 20 mA and the series resistance was reduced by 20%. The light output is increased by the nano-roughening of the top p-GaN surface. The reduction in the series resistance can be attributed to the increase in the contact area of nano-roughened surface.
Increasing the extraction efficiency of AlGaInP LEDs via n-side surface roughening
(2005-11-01)
Lee, YJ
;
Kuo, HC
;
Wang, SC
;
Hsu, TC
;
Hsieh, MH
An n-side-up AlGaInP-based light-emitting diode (LED) with a triangle-like surface morphology was fabricated using the adhesive layer bonding technique, followed by wet etching to roughen the surface. The light output power of the roughened-surface LED was 1.6 times higher than that of a flat-surface LED at an injection current of 20 mA, i.e., a significant improvement attributed to the ability of the roughened surface to not only reduce the internal reflection between the rear mirror system and the semiconductor-air interface, but also to effectively scatter the light outside the LED device.
Improvement in light-output efficiency of AlGaInP LEDs fabricated on stripe patterned epitaxy
(2005-12-01)
Lee, YJ
;
Tseng, HC
;
Kuo, HC
;
Wang, SC
;
Chang, CW
Quaternary AlGaInP light-emitting diodes (LEDs) operating at a wavelength of 630 nm with a stripe-patterned omni-directional reflector (ODR) were fabricated. It is demonstrated that the geometrical shape of stripe-patterned structure improves the light extraction efficiency by increasing the extraction of guided light. The optical and electrical characteristics of stripe-patterned ODR LEDs are presented and compared to typical ODR and distributed Bragg reflector (DBR) LEDs with the same epitaxial structure and emitting wavelength. It is shown that the output power of the stripe-patterned ODR LED exceeds that of the typical ODR and DBR LEDs by a factor of 1.15 and 2 times, respectively, and with an acceptable forward voltage of about 2.2 V.
GaN-based LEDs with Al-deposited V-shaped sapphire facet mirror
(2006-03-01)
Lee, YJ
;
Hwang, JM
;
Hsu, TC
;
Hsieh, MH
;
Jou, MJ
A GaN-based light-emitting diodes (LEDs) with V-shaped sapphire facet reflector was fabricated using the double transferred scheme and sapphire chemical wet etching. The {1-102} R-plane V-shaped facet reflector with a 57 degrees against {0001} C-axis has the superior capability for enhancing the light extraction efficiency. The light output power of the V-shaped sapphire facet reflector LED was 1.4 times higher than that of a flat reflector LED at an injection current of 20 mA. The significant improvement is attributable to the geometrical shape of sapphire facet reflector that efficiently redirects the guided light inside the chip toward to the top escape-cone of the LED surface.
Enhanced light output in InGaN/GaN light emitting diodes with excimer laser etching surfaces
(2006-04-01)
Huang, HW
;
Chu, JT
;
Kao, CC
;
Hsueh, TH
;
Lu, TC
The InGaN/GaN light-emitting diode (LED) with a top p-GaN surface nanoroughened using Ni nanomasks and laser etching has been fabricated. The light output power of the InGaN/GaN LED with a nanoroughened top p-GaN surface is 1.55-fold that of a conventional LED. The series resistance of InGaN/GaN LED was reduced by 32% due to the increase in the contact area of the nanoroughened surface.
Enhancing the output power of GaN-based LEDs grown on wet-etched patterned sapphire substrates
(2006-05-01)
Lee, YJ
;
Hwang, JM
;
Hsu, TC
;
Hsieh, MH
;
Jou, MJ
GaN-based light-emitting diodes (LEDs) with emitting wavelength of 450 nm were grown on patterned sapphire substrates (PSSs) fabricated by chemical wet etching. The crystallography-etched facet was {1-102} R-plane with a 57 degrees against {001} C-axis and had superior capability for enhancing light extraction efficiency. The light output power of the PSS LED was 1.15 times higher than that of the conventional LED at an injection current of 20 mA. The output power and external quantum efficiency were estimated to be 9 mW and 16.4%, respectively. The improvement was attributed not only to geometrical shapes of {1-102} crystallography-etched facets that efficiently scatter the guided light to find escape cones, but also to dislocation density reduction by adopting the PSS growth scheme.

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🏛️國立陽明交通大學機構典藏

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