Browsing by Author "Wu, Yun-Lin"

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Characteristics of an Electrically Pumped GaN-based Microcavity Light Emitter with an AlN Current Blocking Layer
(2012)
Cheng, Bo-Siao
;
Wu, Tzeng-Tsong
;
Lai, Ying-You
;
Wu, Yun-Lin
;
Chen, Cheng-Hung
We demonstrate a GaN-based microcavity light emitter (MCLE) with an AlN current blocking layer. An AlN layer is inserted on the InGaN/GaN multiple quantum wells as a current blocking layer and an optical confinement layer. (C)2011 Optical Society of America
Enhanced Output Power of GaN-Based Resonance Cavity Light-Emitting Diodes With Optimized ITO Design
(2011-12-15)
Wu, Tzeng-Tsong
;
Lin, Chien-Chung
;
Wu, Yun-Lin
;
Chen, Chien-Kang
;
Lu, Tien-Chang
We fabricated and measured GaN-based resonant cavity light-emitting diodes with a 30 nm thick Indium tin oxide (ITO) thin film as a transparent contact layer. Four different ITO structures on p-type GaN samples were deposited by sputter and e-gun, and the corresponding device performance was compared. Each of these four samples has been annealed by its optimal parameters. The ITO thin film deposited by sputter demonstrated better electrical characteristics, surface morphology, specific contact resistance, and the overall device light output compared to those of the e-gun samples. Between the two sputtered ITO types, the hybrid type shows higher roll-over current density of 14 kA/cm(2), and the output power is increased from 15 to 39 mu W. From statistical data of the 2-D light intensity under the same current, we saw the lateral current spreading of the pure crystalline ITO by sputter is worst. The hybrid type, which combines the crystalline and amorphous ITO, has the best overall performance when we consider all the electrical, optical, and metrology measurements. From these results, we believe the 30 nm thick hybrid ITO thin film has the best potential to be applied in light emitting devices such as light-emitting diodes, laser diodes, etc.
High Q microcavity light emitting diodes with buried AlN current apertures
(2011-07-25)
Cheng, Bo-Siao
;
Wu, Yun-Lin
;
Lu, Tien-Chang
;
Chiu, Ching-Hsueh
;
Chen, Cheng-Hung
We demonstrate a GaN-based high-Q microcavity light emitting diode (MCLED) with a buried AlN current aperture. A thin AlN layer is inserted on the InGaN/GaN multiple quantum wells as a current blocking layer and an optical confinement layer. The GaN-based MCLED is composed of a 29-pair GaN/AlN distributed Bragg reflector (DBR), an eight-pair of SiO(2)/Ta(2)O(5) dielectric DBR, and a three-lambda optical thickness InGaN/GaN active region. The current can be injected more effectively in the MCLED with a buried AlN current aperture. The output emission has a dominant emission peak wavelength at 440 nm with a very narrow linewidth of 0.52 nm, corresponding to a cavity Q-value of 846 at a driving current of 5 mA. (C) 2011 American Institute of Physics. [doi:10.1063/1.3617418]
Light Output Enhancement of UV Light-Emitting Diodes With Embedded Distributed Bragg Reflector
(2011-05-15)
Cheng, Bo-Siao
;
Chiu, Ching-Hsueh
;
Lo, Ming-Hua
;
Wu, Yun-Lin
;
Kuo, Hao-Chung
We demonstrate the output power enhancement of ultraviolet light-emitting diodes (UVLEDs) by epitaxial lateral over-growth (ELOG) on a distributed Bragg reflector (DBR) patterned substrate. The patterned DBR mesas are used as ELOG masks to improve material quality as well as reflectors to enhance the light output coupling. Compared with the conventional UVLEDs, the surface pit density of UVLEDs at regions right above embedded patterned DBR were reduced from 2.5 x 10(6) to 1.6 x 10(6) cm(-2). The improved light extraction efficiency is verified by ray tracing simulation. The luminous intensity of this novel structure is enhanced by 75% compared to that of reference UVLED structure at the wavelength 390 nm.
Light Output Enhancement of UV Light-Emitting Diodes With Embedded Distributed Bragg Reflector
(2011-05-15)
Cheng, Bo-Siao
;
Chiu, Ching-Hsueh
;
Lo, Ming-Hua
;
Wu, Yun-Lin
;
Kuo, Hao-Chung
We demonstrate the output power enhancement of ultraviolet light-emitting diodes (UVLEDs) by epitaxial lateral over-growth (ELOG) on a distributed Bragg reflector (DBR) patterned substrate. The patterned DBR mesas are used as ELOG masks to improve material quality as well as reflectors to enhance the light output coupling. Compared with the conventional UVLEDs, the surface pit density of UVLEDs at regions right above embedded patterned DBR were reduced from 2.5 x 10(6) to 1.6 x 10(6) cm(-2). The improved light extraction efficiency is verified by ray tracing simulation. The luminous intensity of this novel structure is enhanced by 75% compared to that of reference UVLED structure at the wavelength 390 nm.