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转移基板材质对Si衬底GaN基LED芯片性能的影响 总被引:7,自引:4,他引:3
在Si衬底上生长了GaN基LED外延材料,分别转移到新的硅基板和铜基板上,制备了垂直结构蓝光LED芯片。研究了这两种基板GaN基LED芯片的光电性能。在切割成单个芯片之前,对大量尺寸为(300μm×300μm)的这两种芯片分别通高达1 A的大电流在测试台上加速老化1 h。结果显示,铜基板Si衬底GaN基LED芯片有更大的饱和电流,光输出效率更高,工作电压随驱动电流的变化不大,光输出在老化过程中衰减更小。铜基板芯片比硅基板芯片可靠性更高,在大功率半导体照明器件中前景诱人。 相似文献
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《中国光学与应用光学文摘》2007,(1)
O484.12007010582δ掺杂对Si衬底GaN蓝光LED外延膜性能的影响研究=Effect ofδ-doping on performance of GaN blue LED epi-taxial fil ms on Si substrates[刊,中]/程海英(南昌大学教育部发光材料与器件工程研究中心.江西,南昌(330047)),方文卿…//光学学报.—2006,26(8).—1269-1273用X射线衍射方法通过不同晶面的ω扫描测试,分析了Si衬底GaN蓝光LED外延膜中n-型层δ掺杂Si处理对外延膜结晶性能的影响。报道了Si衬底GaN外延膜系列晶面的半峰全宽(FWHM)值。通过使用晶格-旋转(Lattice-rotation)模型拟合,计算出样品的螺位错密… 相似文献
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Si衬底功率型GaN基绿光LED性能 总被引:3,自引:3,他引:0
对本实验室在Si(111)衬底上MOCVD法生长的芯片尺寸为400 μm×600μm功率型绿光LED的光电性能进行研究.带有银反射镜的LED在20 mA的电流下正向工作电压为3.59 V,主波长518 nm,输出光功率为7.3 mW,90 mA下达到28.2 mW,发光功率效率为7.5%,光输出饱和电流高达600 mA.在200 mA电流下加速老化216 h,有银反射镜的LED光衰小于尤银反射镜的LED,把这一现象归结于Ag反射镜在提高出光效率的同时,降低了芯片奉身的温度.本器件有良好的发光效率,光衰和光输出饱和电流等综合特性表明,Si衬底GaN基绿光LED具有诱人的发展前景. 相似文献
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用X射线衍射方法通过不同晶面的ω扫描测试,分析了Si衬底GaN蓝光LED外延膜中n-型层δ掺杂Si处理对外延膜结晶性能的影响。报道了Si衬底GaN外延膜系列晶面的半峰全宽(FWHM)值。通过使用晶格旋转(Lattice-rotation)模型拟合,计算出样品的螺位错密度和刃位错密度。结果表明,δ掺杂Si处理后生长出的样品螺位错密度增大、刃位错密度减小,总位错密度有所减小。通过对未经δ掺杂处理和δ掺杂处理的GaN外延膜相应ω-2θ扫描半峰全宽值的比较,发现δ掺杂Si处理后生长出的样品非均匀应变较大;相应样品的LED电致发光光谱I、-V特性曲线显示δ掺杂后样品性能变好。 相似文献
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激光剥离技术实现垂直结构GaN基LED 总被引:3,自引:0,他引:3
为改善GaN基发光二极管(Light-emitting diode,LED)的电学特性和提高其输出光功率,采用激光剥离技术,在KrF准分子激光器脉冲激光能量密度为400mJ/cm2的条件下,将GaN基LED从蓝宝石衬底剥离,结合金属熔融键合技术,在300℃中将GaN基LED转移至高电导率和高热导率的硅衬底,制备出了具有垂直结构的GaN基LED,并对其电学和光学特性进行了测试。结果表明:在110mA注入电流下,垂直结构器件的开启电压由普通结构的3.68V降低到了3.27V;在560mA注入电流下,器件输出光功率没有出现饱和现象;采用高电导率和高热导率的硅衬底能有效地改善GaN基LED的电学和光学特性。 相似文献
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GaN基发光二极管(LED)中的残余应力状态对器件的性能和稳定性有很大影响. 通过使用三种不同的键合衬底(Al2O3衬底, CuW衬底和Si衬底)以及改变键合温度(290 ℃, 320 ℃, 350 ℃和380 ℃), 并且使用不同的激光能量密度(875, 945和1015 mJ·cm-2) 进行激光剥离, 制备了不同应力状态的GaN基LED器件. 对不同条件下GaN LED进行弯曲度、Raman 散射谱测试. 实验结果表明, 垂直结构LED中的残余应力的状态是键合衬底和键合金属共同作用的结果, 而键合温度影响着垂直结构LED中的残余应力的大小. 激光剥离过程中, 一定能量密度下激光剥离工艺一般不会对芯片中的残余应力造成影响, 但是如果该工艺对GaN 层造成了微裂缝, 则会在一定程度上起到释放残余应力的作用. 使用Si衬底键合后, 外延蓝宝石衬底翘曲变大, 对应制备的GaN基垂直结构 LED中的残余应力为张应力, 并且随着键合温度的上升而变大; 而Al2O3和CuW衬底制备的LED中的残余应力为压应力, 但使用Al2O3衬底键合制备的LED中压应力随键合温度上升而一定程度变大, CuW 衬底制备的LED中压应力随键合温度上升而下降. 相似文献
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Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide 总被引:1,自引:0,他引:1
Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs. 相似文献
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A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output. 相似文献
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S. G. Nedel’ko M. A. Krysyuk A. L. Apanasenko L. N. Lymarenko Z. T. Moroz 《Journal of Applied Spectroscopy》1997,64(1):55-61
Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped
with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly
described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation
(5.5·104 Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum
cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics
of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure
crystals is analyzed (preliminarily).
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997. 相似文献
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The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper. 相似文献
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A multi-conjugate adaptive optics (MCAO) can offer a possibility of widening field of view (FOV) characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle's expressions of two deformable mirrors (DMs) MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance. 相似文献
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Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use. 相似文献
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We measure the waveform and phase curves of short optical pulses before and after transmission over different lengths of fibers by use of the pulse analyzer with the frequency-resolved optical gating (FROG),and numerically simulate pulse evolution under the experimental conditions.The nonlinear coefficient of the fiber is given by comparing the experimental results with the numerical ones.Difference between the experiment and numerical simulation is analyzed. 相似文献
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Resonance scattering of elastic spherical shell and cylindrical shell while the surrounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable result would be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surrounding fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little influence on the low-frequency resonance scattering induced by the filler inside the shell. 相似文献