共查询到19条相似文献,搜索用时 163 毫秒
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分析了隧道再生双有源区A lG aInP发光二极管的工作原理,测试了不同注入电流下管芯的轴向光强,得到了轴向光强随注入电流的变化关系。20 mA注入电流条件下,发射峰值波长为620 nm的隧道再生双有源区A lG aInP发光二极管,透明封装成视角15°后平均轴向光强达到5.5 cd。对透明封装成15°隧道再生双有源区发光二极管进行了寿命实验,在温度为25°C、30 mA直流电流条件下,隧道再生双有源区A lG aInP发光二极管的寿命超过了1.2×105h。 相似文献
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分析了薄膜发光二极管中光子的路径,对比了AlGaInP薄膜发光二极管的反光镜有无AlGaInP层的反射率,分析了AlGaInP层的吸收并计算了光提取效率。制作了不同GaP厚度的TF AlGaInP LED。在20mA的驱动电流下,0.6μm GaP的LED比8μm GaP 的LED光输出功率高33%。提出了在0.6μm GaP的LED中腐蚀去除非欧姆接触点处的重掺GaP。在n型电极和p型欧姆接触点间的电流扩展的设计和优化需要更进一步的研究。 相似文献
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根据白光照明和可变换波长的光通信中对单芯片双波长发光二极管(LED)要求,在分析了反向偏置隧道结性质的基础上,设计了用反向偏置隧道结连接两个有源区的单芯片双波长LED,用金属有机化学气相沉积技术(MOCVD)在GaAs衬底上一次外延生长了同时发射两种波长的LED,其包含一个AlGaInP量子阱有源区和一个GaInP量子阱有源区,两个有源区由隧道结连接;通过后工艺制备了双波长LED器件,在20mA电流注入下,可以同时发射626nm和639nm两种波长,光强是127mcd,正向电压是4.17V。与传统的单有源区LED进行对比表明,双波长LED有较强的光强;对比单有源区LED的2.08V正向电压,考虑到双波长LED包含隧道结和两个有源区,隧道结上的压降很小。 相似文献
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《电子科技文摘》2006,(7)
0617068作为双光子吸收装置的Si雪崩光电二极管无背景强度自动相关器=Background-free intensity autocorrelatoremploying Si avalanche photodiode as two-photon ab-sorber〔刊,英〕/K.Taira,Y.Fukuchi//Electronics Let-ters.—2002,38(23).—1465(E)0617069高特性1500V4H-SiC结势垒Schottky二极管=Highperformance1500V4H-SiC junction barrier Schottkydiodes〔刊,英〕/J.H.Zhao,P.Alexandrov//ElectronicsLetters.—2002,38(22).—1389(E)0617070隧道再生双有源区AIGaInP发光二极管提取效率的计算〔刊,中〕/田咏桃//固… 相似文献
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Windisch R. Butendeich R. Illek S. Kugler S. Wirth R. Zull H. Streubel K. 《Photonics Technology Letters, IEEE》2007,19(10):774-776
Thin-film light-emitting diodes (LEDs) belong to the most successful LED concepts for achieving high efficiencies. The incorporation of buried microreflectors with inclined facets prevents the light generation under the top contact and bondpad and offers an additional light extraction scheme. As a result, an external quantum efficiency of 50% could be demonstrated at a wavelength of 650 nm, and a luminous efficiency of more than 100 lm/W could be achieved in the wavelength range from 595 to 620 nm 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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Chien-Chun Wang Hung-Chi Lu Chien-Chih Liu Fenq-Lin Jenq Yeong-Her Wang Mau-Phon Houng 《Photonics Technology Letters, IEEE》2008,20(6):428-430
An anodic alumina oxide (AAO) film with nano-roughening is added on the top window layer of AlGaInP light-emitting diodes (LEDs) to improve the light extraction of the device. The AAO film has a natural porosity to provide light scattering centers at the surface, allowing an increase of light emission intensity with no loss of or damage to the semiconductor material. Further, the fabricated AAO film with a refractive index is about which is intermediate between those of air and the window layer of GaP. By inserting this layer between the ambient and GaP, it broadens the critical angle for light emission and reduces internal reflection. Experiments with laboratory-fabricated AlGaInP devices of conventional design demonstrated a 32% improvement in the luminous intensity at 20 mA for the device with the AAO layer. This letter shows by theory and experiment that AAO films can be used as a low-cost, easily implemented surface nano-roughening for improving extraction efficiency of AlGaInP LEDs. 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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Danner A.J. Benzhong Wang Soo-Jin Chua Jeong-Ki Hwang 《Photonics Technology Letters, IEEE》2008,20(1):48-50
A low-cost method of fabricating large photonic crystal arrays of hexagonal posts without the use of lithography is described, along with an application of enhancing light extraction efficiency in semiconductor light-emitting diodes (LEDs). Polystyrene spheres are deposited onto a wafer surface and then processed to achieve control over photonic crystal lattice properties in a method suitable for fast and repeatable patterning. The spheres serve as an etch mask to extend the photonic crystal formed into the semiconductor surface. This technique is applied to LEDs to increase the top surface light extraction, and 51% wall plug enhancement is demonstrated in deep junction liquid phase epitaxially grown LEDs with absorbing substrates, though is adaptable to any substrate and photonic crystal dimensions. 相似文献
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Kim H.G. Cuong T.V. Na M.G. Kim H.K. Kim H.Y. Ryu J.H. Hong C.-H. 《Photonics Technology Letters, IEEE》2008,20(15):1284-1286
GaN-based light-emitting diodes with peripheral microhole arrays (PMA-LEDs) have been grown, and fabricated, on SiO2 hexagonal pattern masks using selective metal-organic chemical vapor deposition. The PMA-LED structure promises to enhance the light extraction efficiency via simple fabrication processes, as compared to conventional LED structures. The geometrical shape of the peripheral microhole structure serves to enhance the light extraction efficiency due to the effect of the PMA in facilitating multiple chances for photons to escape. Thus, the light output intensity of PMA-LED was 30% higher than that of conventional LEDs. 相似文献
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We have demonstrated nitride-based near-ultraviolet mesh multiquantum-well (MQW) light-emitting diodes (LEDs) by etching through the MQW active region. With 20-mA injection current, it was found that forward voltages were 3.29, 3.31, and 3.38 V while output powers were 7.5, 9.0, and 11.3 mW for the planar indium-tin-oxide (ITO) LED, mesh ITO LED, and mesh MQW LED, respectively. The larger LED output power is attributed to the increased light extraction efficiency. 相似文献
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In this study, a trapezoidal-shaped electron blocking layer is proposed to improve efficiency droop of InGaN/GaN multiple quantum well light-emitting diodes. The energy band diagram, carrier distribution profile, electrostatic field, and electron current leakage are systematically investigated between two light-emitting diodes with different electron blocking layer structures. The simulation results show that, when traditional AlGaN electron blocking layer is replaced by trapezoidal-shaped electron blocking layer, the electron current leakage is dramatically reduced and the hole injection efficiency in markedly enhanced due to the better polarization match, the quantum-confined Stark effect is mitigated and the radiative recombination rate is increased in the active region subsequently, which are responsible for the alleviation of efficiency droop. The optical performance of light-emitting diodes with trapezoidal-shaped electron blocking layer is significantly improved when compared with its counterpart with traditional AlGaN electron blocking layer. 相似文献
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A.J. Shaw A.L. Bradley J.F. Donegan J.G. Lunney 《Photonics Technology Letters, IEEE》2004,16(9):2006-2008
The optical designs of resonant GaN light-emitting diodes (LEDs) have been determined for maximum extraction efficiency into typical plastic optical fiber of numerical aperture 0.5. An optimum extraction efficiency of 3.9% can be achieved for a practical resonant cavity LED (RCLED), taking account of current growth and processing considerations. The optimized device is a metal-active layer distributed Bragg reflector construction. Constructive interference effects from the top metal mirror are found to play the dominant role in efficiency enhancement. The extraction efficiency of an optimized resonant single-mirror LED is found to be 3.3%, indicating a small compromise in performance compared with the more complex RCLED structure. 相似文献