共查询到20条相似文献,搜索用时 125 毫秒
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基于时域有限差分法(FDTD)在GaN基LED表面分别生长了 ZnO柱状与锥状微纳结构,并利用Rsoft模拟仿真软件分析了两种结构的几何参量(排列周期p、高度H、底面直径D等)对GaN基LED光提取效率的影响.结果表明两种结构均可提高器件的光提取效率,柱状结构在H=0.25 μm,p=1.5 μm,D=0.9μm时表现最优,其光提取效率是未加任何结构平板LED的5.6倍;而锥状结构在H=0.6μm,p=1.4 μm,D=1.4 μm时表现最优,其光提取效率是未加任何结构平板LED的5.3倍.研究结果对高性能GaN基LED的设计与制备具有一定指导意义. 相似文献
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《量子电子学报》2014,(1)
正设计并研制了光子晶体结构GaN LED,实现了光子晶体GaN LED提取效率的提高及其到胶体量子点的共振能量转移,能量转移效率达到79.50%。设计了光子晶体GaN LED器件结构,利用光刻、感应耦合等离子体刻蚀等工艺研制了光子晶体GaN LED器件,制作的光子晶体区域边缘光滑,满足实验的要求。采用积分球收集LED发光来测试LED的P-I-V曲线,测试了在p-GaN上刻蚀光子晶体的LED在不同电流下输出功率与晶格常数、占空比的关系。研究发现:50 mA驱动电流下,晶格常数为14μm、半径与晶格常数比为0.25的光子晶体GaN LED输出功率比无光子晶体GaN LED提高21%以上。该研究对实现高效率胶体量子点电注入发光器件具有借鉴价值。 相似文献
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设计了方形和阶梯状两大类的图形化蓝宝石衬底(PSS), 使用Crosslight公司的工艺软件CSuprem建立了三维的方形和阶梯状两类图形衬底GaN LED器件, 然后使用APSYS软件模拟计算出它们的光电特性。并且对方形图形衬底的刻蚀深度进行了优化, 通过对模拟结果的比较得到刻蚀深度与边长的比值为0.4时, 这种方形图形衬底GaN LED的光提取效率最高, 且比平面衬底提高了20.13%。对阶梯状图形衬底的阶梯层数进行了比较, 发现随着阶梯层数的增加, 光提取效率也随着增加, 阶梯状层数为5时, 光提取效率比平面衬底提高了30.03%。并对方形PSS LED进行了实验验证。 相似文献
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通过对传统结构LED出光分析,提出采用侧面粗化来提高GaN基LED出光效率的方法,使用蒙特卡罗光子追踪方法对器件出光效率进行了模拟。结果表明:粗化侧面为三角状、底角为55°时出光效率最高,随机粗化可以获得比固定角度粗化更高的出光效率,同时降低材料的吸收系数可以提高LED的出光效率,在吸收系数为10/cm时,经过粗化后的LED出光效率可以达到46.1%。模拟结果证明侧面粗化可以较大地提高LED的出光效率。 相似文献
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Periyayya Uthirakumar Ji Hye Kang Beo Deul Ryu Chang-Hee Hong 《Materials Science in Semiconductor Processing》2010,13(5-6):329-332
Light extraction efficiency of GaN-based light emitting diodes (LEDs) has improved significantly by using ITO/ZnO layer texturing. We have deliberately designed and successfully fabricated GaN-based LEDs having one and two interfaces of ITO/ZnO layer texturing in the device structure. It was found that the light extraction efficiencies of one and two interfaces of ITO/ZnO-layer texturing LEDs were 22.29% and 35.54% at 20 mA of current injection, respectively. Creating the chances of multiple light scattering at more than one interface is playing a major role to enhance light output power of the device. The source of the enhanced light output power is also discussed. 相似文献
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Two foundational factors (escape cone and transmissivity) about light extraction of light emitting diodes (LEDs) are discussed.According to these factors,a new process to simulate the light extraction of LEDs based on the Monte Carlo method has been provided.The improved method is to deal with the reflection and refraction of light (beam of light) at the interface between two mediums approximately.In addition,light extraction of traditional LEDs is simulated by different processes with the same structure and parameters.The results show that the reflection and refraction of light processed approximately are accurate enough for analyzing LEDs structure.This method saves much time and improves efficiency in the simulation of light extraction of LEDs. 相似文献
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Analysis and Simulation of Light Extraction of Light-Emitting Diodes: Simulation Efficiency
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Two foundational factors (escape cone and transmissivity) about light extraction of light emitting diodes (LEDs) are discussed. According to these factors, a new process to simulate the light extraction of LEDs based on the Monte Carlo method has been provided. The improved method is to deal with the reflection and refraction of light (beam of light) at the interface between two mediums approximately. In addition, light extraction of traditional LEDs is simulated by different processes with the same structure and parameters. The results show that the reflection and refraction of light processed approximately are accurate enough for analyzing LEDs structure. This method saves much time and improves efficiency in the simulation of light extraction of LEDs. 相似文献
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Liann-Be Chang Yuan-Hsiao Chang Ming-Jer Jeng 《Photonics Technology Letters, IEEE》2007,19(15):1175-1177
We propose a microchannel structure with deep holes to enhance the extraction efficiency of InGaN-based light-emitting diodes (LEDs). Two different depth microchannel LEDs are examined experimentally. One has air holes penetrated through the active layer and the other does not. It is found that the light extraction efficiency in the LED with the penetrated air holes is significant h larger than that in the LED without penetrating holes. The reason can be attributed to the microchannel waveguide behaviors. In comparison to the conventional LEDs, the light output power of our fabricated LEDs with and without penetrating holes improved by 43.5% and 5.1%, respectively. 相似文献
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To enhance the light extraction efficiency of traditional light-emitting diodes(LEDs) by reducing the total internal reflection,an omni-directional reflector(ODR) and photonic crystal are adopted in the paper.The structures of photonic crystal and the ODR are designed by diffraction theory and finite difference time domain(FDTD) method.The photonic crystal is employed in the p-GaN layer and the ODR composed of TiO2/SiO2 is designed between the active region and substrate.The simulation results indicate that the light extraction of LEDs can be enhanced by 11.6 times,and the external quantum efficiency of LEDs will be effectively improved. 相似文献
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Haiyong Gao Fawang Yan Yang Zhang Jinmin Li Yiping Zeng Guohong Wang 《Solid-state electronics》2008,52(6):962-967
Sapphire substrates patterned by a selective chemical wet and an inductively coupled plasma (ICP) etching technique was proposed to improve the performance of GaN-based light-emitting diodes (LEDs). GaN-based LEDs were fabricated on sapphire substrates through metal organic chemical vapor deposition (MOCVD). The LEDs fabricated on the patterned substrates exhibit improved device performance compared with the conventional LED fabricated on planar substrates when growth and device fabricating conditions were the same. The light output powers of the LEDs fabricated on wet-patterned and ICP-patterned substrates were about 37% and 17% higher than that of LEDs on planar substrates at an injection current of 20 mA, respectively. The enhancement is attributable to the combination of the improvement of GaN-based epilayers quality and the improvement of the light extraction efficiency. 相似文献
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Efficiency Improvement of GaN-Based LEDs With $ hbox{SiO}_{2}$ Microrod Array and Textured Sidewalls
Chien-Chih Kao Yan-Kuin Su Chuing-Liang Lin Jian-Jhong Chen 《Electron Device Letters, IEEE》2010,31(1):35-37
High-performance nitride-based light-emitting diodes (LEDs) grown with SiO2 microrod array have been demonstrated. The light output power of LEDs with SiO2 microrod array was 9.03% higher than conventional LEDs at the injection current of 20 mA. The improvement contributed to the enhancement of the light extraction efficiency, and epitaxial GaN film quality improved by direct heteroepitaxial lateral overgrowth with SiO2 microrod array. The light output power could be further enhanced by about 18.36% as compared with the conventional LEDs when adopting the textured sidewall surface which use buffered oxide etch to remove SiO2 microrod arrays and use NaOH to etch the sidewall again into an inverted pyramid shape. After the texturing process, the LEDs show higher electroluminescence intensity and broader far-field pattern. Furthermore, the LEDs with SiO2 microrod array and additional wet-etching process will not affect the electrical property. 相似文献