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Large-scale SiO_2 photonic crystal for high efficiency GaN LEDs by nanospherical-lens lithography
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作者 吴奎 魏同波 +4 位作者 蓝鼎 郑海洋 王军喜 罗毅 李晋闽 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第2期566-569,共4页
Wafer-scale SiO2 photonic crystal (PhC) patterns (SiO2 air-hole PhC, SiO2-pillar PhC) on indium tin oxide (ITO) layer of GaN-based light-emitting diode (LED) are fabricated via novel nanospherical-lens lithogr... Wafer-scale SiO2 photonic crystal (PhC) patterns (SiO2 air-hole PhC, SiO2-pillar PhC) on indium tin oxide (ITO) layer of GaN-based light-emitting diode (LED) are fabricated via novel nanospherical-lens lithography. Nanoscale polystyrene spheres are self-assembled into a hexagonal closed-packed monolayer array acting as convex lens for expo- sure using conventional lithography instrument. The light output power is enhanced by as great as 40.5% and 61% over those of as-grown LEDs, for SiO2-hole PhC and SiO2-pillar PhC LEDs, respectively. No degradation to LED electrical properties is found due to the fact that SiO2 PhC structures are fabricated on ITO current spreading electrode. For SiO2- pillar PhC LEDs, which have the largest light output power in all LEDs, no dry etching, which would introduce etching damage, was involved. Our method is demonstrated to be a simple, low cost, and high-yield technique for fabricating the PhC LEDs. Furthermore, the finite difference time domain simulation is also performed to further reveal the emission characteristics of LEDs with PhC structures. 展开更多
关键词 InGaN light-emitting diodes (leds) photonic crystal nanosphere lithography FDTD simulation
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Progress and prospects of GaN-based LEDs using nanostructures
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作者 赵丽霞 于治国 +6 位作者 孙波 朱石超 安平博 杨超 刘磊 王军喜 李晋闽 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第6期83-94,共12页
Progress with GaN-based light emitting diodes (LEDs) that incorporate nanostructures is reviewed, especially the re- cent achievements in our research group. Nano-patterned sapphire substrates have been used to grow... Progress with GaN-based light emitting diodes (LEDs) that incorporate nanostructures is reviewed, especially the re- cent achievements in our research group. Nano-patterned sapphire substrates have been used to grow an A1N template layer for deep-ultraviolet (DUV) LEDs. One efficient surface nano-texturing technology, hemisphere-cones-hybrid nanostruc- tures, was employed to enhance the extraction efficiency of InGaN flip-chip LEDs. Hexagonal nanopyramid GaN-based LEDs have been fabricated and show electrically driven color modification and phosphor-free white light emission because of the linearly increased quantum well width and indium incorporation from the shell to the core. Based on the nanostruc- tures, we have also fabricated surface plasmon-enhanced nanoporous GaN-based green LEDs using AAO membrane as a mask. Benefitting from the strong lateral SP coupling as well as good electrical protection by a passivation layer, the EL intensity of an SP-enhanced nanoporous LED was significantly enhanced by 380%. Furthermore, nanostructures have been used for the growth of GaN LEDs on amorphous substrates, the fabrication of stretchable LEDs, and for increasing the 3-dB modulation bandwidth for visible light communication. 展开更多
关键词 GaN-based light emitting diodes (leds) NANOSTRUCTURE nano-patterned sapphire substrate sur-face plasmon
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Evaluation of current and temperature effects on optical performance of InGaAlP thin-film SMD LED mounted on different substrate packages
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作者 Muna E.Raypah Mutharasu Devarajan Fauziah Sulaiman 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第7期454-460,共7页
The relationship between the photometric, electric, and thermal parameters of light-emitting diodes(LEDs) is important for optimizing the LED illumination design. Indium gallium aluminium phosphide(InGaAlP)-based ... The relationship between the photometric, electric, and thermal parameters of light-emitting diodes(LEDs) is important for optimizing the LED illumination design. Indium gallium aluminium phosphide(InGaAlP)-based thin-film surface-mounted device(SMD) LEDs have attracted wide attention in research and development due to their portability and miniaturization. We report the optical characterization of InGaAlP thin-film SMD LED mounted on FR4, 2 W, and 5 W aluminum(Al) packages. The optical and thermal parameters of LED are determined at different injection currents and ambient temperatures by combining the T3ster(thermal transient tester) and TeraL ED(thermal and radiometric characterization of power LEDs) systems. Analysis shows that LED on a 5 W Al substrate package obtains the highest luminous and optical efficiency. 展开更多
关键词 light-emitting diodes(leds) surface-mounted device(SMD) INGAALP luminous efficiency
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Performance improvement of GaN-based light-emitting diode with a p-InAlGaN hole injection layer
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作者 喻晓鹏 范广涵 +4 位作者 丁彬彬 熊建勇 肖瑶 张涛 郑树文 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第2期557-560,共4页
The characteristics of a blue light-emitting diode (LED) with a p-InA1GaN hole injection layer (HIL) is analyzed numerically. The simulation results indicate that the newly designed structure presents superior opt... The characteristics of a blue light-emitting diode (LED) with a p-InA1GaN hole injection layer (HIL) is analyzed numerically. The simulation results indicate that the newly designed structure presents superior optical and electrical performance such as an increase in light output power, a reduction in current leakage and alleviation of efficiency droop. These improvements can be attributed to the p-InA1GaN serving as hole injection layers, which can alleviate the band bending induced by the polarization field, thereby improving both the hole injection efficiency and the electron blocking efficiency. 展开更多
关键词 InGaN light-emitting diodes (leds) p-InA1GaN hole injection layer (HIL) numerical simulation
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Fabrication and characteristics of excellent current spreading GaN-based LED by using transparent electrode-insulator-semiconductor structure 被引量:2
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作者 Chenglin Qi Yang Huang +3 位作者 Teng Zhan Qinjin Wang Xiaoyan Yi Zhiqiang Liu 《Journal of Semiconductors》 EI CAS CSCD 2017年第8期44-48,共5页
GaN-based vertical light-emitting-diodes (V-LEDs) with an improved current injection pattern were fabricated and a novel current injection pattern of LEDs which consists of electrode-insulator-semiconductor (E1S) ... GaN-based vertical light-emitting-diodes (V-LEDs) with an improved current injection pattern were fabricated and a novel current injection pattern of LEDs which consists of electrode-insulator-semiconductor (E1S) structure was proposed. The EIS structure was achieved by an insulator layer (20-nm Ta2O5) deposited between the p-GaN and the ITO layer. This kind of EIS structure works through a defect-assisted tunneling mechanism to realize current injection and obtains a uniform current distribution on the chip surface, thus greatly improving the current spreading ability of LEDs. The appearance of this novel current injection pattern of V-LEDs will subvert the impression of the conventional LEDs structure, including simplifying the chip manufacture technology and reducing the chip cost. Under a current density of 2, 5, 10, and 25 A/cm2, the luminous uniformity was better than conventional structure LEDs. The standard deviation of power density distribution in light distribution was 0.028, which was much smaller than that of conventional structure LEDs and illustrated a huge advantage on the current spreading ability of EIS-LEDs. 展开更多
关键词 electrode-insulator-semiconductor (EIS) light emitting diodes (leds) tunneling mechanism lumi-nous unifomaity current spreading
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Self-adaptive phosphor coating technology for white LED packaging 被引量:2
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作者 Haibo RAO Kun DING +5 位作者 Jirong SONG Likun XIE Wei WANG Xianlong WAN Linsong ZHOU Junyuan LIAO 《Frontiers of Optoelectronics》 2012年第2期147-152,共6页
Phosphor-converted light-emitting diodes (pc- LEDs), which employ blue LEDs with yellow phosphors to generate white light illumination, is a widely used solid- state lighting source. In order to conduct a phosphor l... Phosphor-converted light-emitting diodes (pc- LEDs), which employ blue LEDs with yellow phosphors to generate white light illumination, is a widely used solid- state lighting source. In order to conduct a phosphor layer coating with high quality on LED chip, a self-adaptive coating technology is introduced in this paper. A slurry coating technique combined with selfexposure method is applied and developed to demonstrate the benefits of selfadaptive coating layer. For self-exposure, the slurry coating is exposed to the blue emission of LED itself other than to ultraviolet (UV) light outside to make photoresist crosslinking. Results of measurement indicate that white LEDs with self-adaptive coating have shown self-adaptability to the angular distribution of intensity of blue light and performed higher spatial color uniformity than those with conventional coating and other conformal coating. 展开更多
关键词 white light-emitting diodes (leds) phosphorcoating SELF-ADAPTIVE slurry method SELF-EXPOSURE
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Ceramic-metal package for high power LED lighting 被引量:2
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作者 Yu Jin HEO Hyo Tae KIM +3 位作者 Sahn NAHM Jihoon KIM Young Joon YOON Jonghee KIM 《Frontiers of Optoelectronics》 2012年第2期133-137,共5页
High power light-emitting diodes (LEDs) lighting has drawn a great interest in the field of street light system in recent years. Key parameters for successful launching of LED street light in the commercial market a... High power light-emitting diodes (LEDs) lighting has drawn a great interest in the field of street light system in recent years. Key parameters for successful launching of LED street light in the commercial market are price and light efficiency, respectively, and they are greatly influenced by the materials and design factors used in high power LED package. This article presents a new design and materials processing technology to realize the solution of LED packaging with advantageous in price and performance. Cost effective materials and processing technology can be realized via thick film glass-ceramic insulating layer and silver conductor. Highly effective thermal design using direct heat dissipation to heat sink in LED package is demonstrated. 展开更多
关键词 light-emitting diodes (leds) package HIGH-POWER thick film heat dissipation thermal resistance
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Effects of packaging structure on optical performances of phosphor converted light emitting diodes 被引量:1
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作者 Xing FU Huai ZHENG +1 位作者 Sheng LIU Xiaobing LUO 《Frontiers of Optoelectronics》 2012年第2期153-156,共4页
Effects of tilt angles of reflective cup structure and phosphor surface geometries on light extraction efficiency and angular color uniformity (ACU) of phosphor converted light emitting diodes (pcLED) are investig... Effects of tilt angles of reflective cup structure and phosphor surface geometries on light extraction efficiency and angular color uniformity (ACU) of phosphor converted light emitting diodes (pcLED) are investigated by Monte Carlo ray-tracing simulations. It is found that tilt angles of reflective cup and phosphor surface geometries affect the light extraction efficiency and the ACU distinctly. When the tilt angle varied from 60° to 15°, the light extraction efficiency of LED can achieve the improvements of 13.87%, 18.25% and 14.79% respectively, when the phosphor surface geometry is concave, flat and convex, respectively. It is also found the variety law of phosphor concentrations with the change of tilt angles and phosphor surface geometries to maintain a fixed correlated color temperature (CCT). 展开更多
关键词 PHOSPHOR packaging structure reflective cup light emitting diodes (leds)
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Enhancement of light output powers of GaN-based light emitting diodes with textured indium tin oxide transparent layer by using corrosive liquid
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作者 LI Yun LI XiaoChan +9 位作者 ZHANG Tao HE AnHe HU CanDong WANG Xin HE Miao ZHANG Yong NIU QiaoLi ZHAO LingZhi LI ShuTi CHEN XianWen 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2011年第10期1787-1790,共4页
In order to promote the light output powers of GaN-based light emitting diodes (LEDs), two kinds of novel corrosive liquidshave been developed in this paper to roughen the surface of the indium tin oxide (ITO) current... In order to promote the light output powers of GaN-based light emitting diodes (LEDs), two kinds of novel corrosive liquidshave been developed in this paper to roughen the surface of the indium tin oxide (ITO) current spreading layer of LEDs. As aresult, the textured transparent ITO layer greatly enhanced the external quantum efficiency of the LEDs. Provided that a wafersample was dipped in a kind of corrosive liquid developed by us for only about 60 s, the light output powers of the LEDs canbe promoted by 24.7%, compared with conventional GaN-based LEDs. It is obvious that the presented method is simple, rapidand cost-effective. 展开更多
关键词 GaN-based light emitting diodes (leds) corrosive liquid light output power textured ITO
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Simple dynamic energy core equivalent rays method to design freeform surface for extended source
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作者 Kun WANG Yanjun HAN +6 位作者 Hongtao LI Yi LUO Zhibiao HAO Lai WANG Changzheng SUN Bing XIONG Jian WANG 《Frontiers of Optoelectronics》 EI CSCD 2016年第2期330-337,共8页
A simple method is proposed to design free- form surface for Lambertian extended source. In this method, it can take advantage of the designing method for point source via substituting each incident ray with a dynamic... A simple method is proposed to design free- form surface for Lambertian extended source. In this method, it can take advantage of the designing method for point source via substituting each incident ray with a dynamically calculated equivalent ray. For each facet on the freeform surface, the equivalent ray emits from the energy weighted average-emitting-position for the corre- sponding incident beam, and redirects into the direction which is determined by a source-to-target mapping. The results of the designing examples show that the light distributions' uniformities can be improved by this method, e.g., even the improvement of 59% can be achieved. 展开更多
关键词 nonimaging optics illumination design lightemitting diodes (leds)
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