Browsing by Author "Chien, Huan-Yu"

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Development and Fabrication of AlGaInP-Based Flip-Chip Micro-LEDs
(2018-01-01)
Horng, Ray-Hua
;
Chien, Huan-Yu
;
Chen, Ken-Yen
;
Tseng, Wei-Yu
;
Tsai, Yu-Ting
The fabrication of AlGaInP-based flip-chip micro light-emitting-diodes (LED; emitting area: 4.5 mil x 5 mil) with horizontal electrodes is reported in this paper. The thickness of the epitaxial layer of the thin LED structure was reduced to 50% of that of the traditional thick LED, whereas carrier concentration in the n-type GaAs contact layer was increased to 5 x 10(18) cm(-3) to meet the Ohmic contact requirement. At a current injection of 5 mA, the thin LED exhibited a forward voltage, output power, and external quantum efficiency of 1.8 V, 1.9 mW, and 19%, respectively. The optoelectronic performance of the thin LED was as good as that of the traditional thick red LED. The technique proposed by this paper can be used to integrate AlGaInP-based LEDs with nitride LEDs for full-color display applications.
Effect of the Phosphor Permanent Substrate on the Angular CCT for White Thin-Film Flip-Chip Light-Emitting Diodes
(2016-10)
Tien, Ching-Ho
;
Ho, Kuo-Wei
;
Chien, Huan-Yu
;
Wuu, Dong-Sing
;
Horng, Ray-Hua
This paper developed a phosphor layer applied for thin-film flip-chip light-emitting diodes (TFFC-LEDs) to produce uniform phosphor-converted TFFC white LEDs (TFFC-WLEDs) by combination of laser liftoff, secondary transferring, and surface roughening process. The spin-coating method was used for phosphor layer fabrication onto a substrate to form the phosphor permanent substrate. The TFFC-LEDs were then bonded onto the permanent substrate. From the results, the blue TFFC GaN-based LED with roughened u-GaN surface on a glass substrate (TFRG-LED) demonstrated a 54.2% (at 350 mA) enhancement in light output power, compared with a blue flip-chip GaN-on-sapphire based LED. As the TFFC GaN/phosphor-/glass-based white LED with roughened u-GaN surface (TFRG-WLED) was operated at a forward-bias current of 350 mA, the enhancement of luminous flux was increased by 75.5%, compared with a TFFC GaN/phosphor template-/glass-based white LED. The angular correlated color temperature (CCT) deviation of a TFRG-WLED can be reduced to 1279 K in the range from -75 degrees to +75 degrees at 5000-6000 K application. The TFRG-WLED was fabricated on the glass substrate with the roughened u-GaN surface and the structure of phosphor layer closed to the u-GaN. These kinds of FRGB-WLED structure contribute to a better light extraction characteristic and a higher CCT stability.
Fabrication and Study on Red Light Micro-LED Displays
(2018-01-01)
Horng, Ray-Hua
;
Chien, Huan-Yu
;
Tarntair, Fu-Gow
;
Wuu, Dong-Sing
;
交大名義發表
A red-light micro LED display made of an AlGaInP epilayer with a resolution of 64 x 32 pixels, a pitch of 175 mu m and a luminous area of 1 cm x 0.5 cm was fabricated and characterized in this study. The AlGaInP epilayer was bonded to double polished sapphire substrate by wafer-bonding technique and then removing the absorbing GaAs substrate. In this design, the ITO was applied as one of the conducting electrodes of the emitting surface, which can be beneficial since the emitting light is not shielded by metal electrodes. The other key process for LED panel fabrication is planarization. Polymer material was used to fill the gap between each pixel, which was used to prevent a short or open circuit using the planarization process. The driving mode of this display is passive multi-electrode addressable controlling. The luminance of this micro-LED panel is more than 450 nits with an operating voltage of 3 V which is three times higher than that of the OLED operating in the same driving mode.