共查询到20条相似文献,搜索用时 93 毫秒
1.
2.
3.
本文就高亮度GaN系蓝色发光二极管研制中的主要问题加以概述,最后对GaN系蓝色半导体激光器的发展做了展望。 相似文献
4.
GaN基蓝光器件的研究进展 总被引:1,自引:0,他引:1
本文对近几年GaN基蓝光器件,包括GaN基发光二极管和激光二极管的发展历程进行了全面介绍和评价。指出GaN基蓝光LED的研究开发技术将在1-2年内走向成熟,从而实现大规模商业化生产,而GaN基蓝光LD也将在近二年内实用化。 相似文献
5.
6.
7.
InGaN/GaN多量子阱蓝光LED电学特性研究 总被引:1,自引:0,他引:1
对不同温度(120~363 K)下InGaN/GaN多量子阱(MQW)结构蓝光发光二极管(LED)的电学特性进行了测试与深入的研究.发现对数坐标下I-V特性曲线斜率随温度变化不大.分别用载流子扩散-复合模型和隧道复合模型对其进行计算,发现室温下其理想因子远大于2,并且随着温度的下降而升高;而隧穿能量参数随温度变化不大.这说明传统的扩散-复合载流子输运模型不再适用于InGaN/GaN MQW蓝光LED.分析指出由于晶格失配以及生长工艺的制约,外延层中具有较高的缺陷密度和界面能级密度,导致其主要输运机制为载流子的隧穿. 相似文献
9.
10.
在图形化衬底上以AlN作为缓冲层生长高质量的GaN薄膜,国内相关的报道较少。通过引入两步缓冲层生长方法,在蓝宝石图形衬底上生长基于AlN缓冲层的高质量GaN薄膜,利用低温AlN层生长时内部的缺陷,选择性进行腐蚀,形成衬底与外延层界面间的侧向倒斜角,提高光萃取效率;同时在其上继续生长高温AlN,为后续GaN薄膜提供高质量模板。从外延角度出发,以表面形貌及其上生长的GaN薄膜的晶体质量为衡量依据,优化了低温AlN缓冲层以及高温AlN缓冲层的生长参数,优化后LED样品在20 mA测试电流下的光输出功率较参考样品提升了4%。 相似文献
11.
12.
在图形化蓝宝石衬底上制备了串联结构的氮化镓(GaN)高压发光二极管(LED),分别在极小电流与极低温度下研究了其光电特性。结果表明,在极小电流区(I<1×10-8 A),主要输运机制为缺陷辅助隧穿。由于能带热收缩效应和辐射复合中心的热激活效应,随着温度升高,电致发光(EL)峰发生红移,半高宽(FWHM)增加;光输出强度与注入电流呈幂指数关系,表明极小电流下非辐射复合占主导,且载流子通过缺陷辅助隧穿至量子阱。在极低温度下(T~40 K)仍能观测到电致发光现象,表明载流子并未被完全冻析,在强场下可由施主态或受主态通过缺陷辅助隧穿至量子阱;随着注入电流增加,注入电荷的库伦电场对极化电场的屏蔽作用增强,导致发光峰发生明显的蓝移,能带填充效应则导致半高宽增加。 相似文献
13.
制作了8milX 10mil的InGaN/GaN 蓝光LED(λ=460nm),采用了真空蒸镀在P-GaN上淀积了240nm的ITO。对不同温度下(100℃至550℃)热退火ITO的电学特性和光学特性进行了比较分析。实验发现,450℃下热退火ITO电阻率低至1.19X10-4Ω?cm,而此温度下得到高透射率94.17%。在20mA注入电流下,正向电压和输出功率分别为3.14V and 12.57mW。另外,550℃ITO退火下制备的LED光通量最大,为0.49lm,这是因为此温度下透射率较大。 相似文献
14.
W. E. Caelos E. R. Glaser T. A. Kennedy S. Nakamura 《Journal of Electronic Materials》1996,25(5):851-854
We report the application of electrical detection of magnetic resonance (EDMR) and electroluminescence detection of magnetic
resonance (ELDMR) to study the recombination processes in InGaN/AlGaN double heterostructure p-n junctions. These techniques
are especially well suited to the problems of defects in device structures in that they are much more sensitive than conventional
paramagnetic resonance and are responsive to only those defects involved in the electrooptical properties of the structure.
One resonance is observed at g≈2.00 and is identified as a Zn-related acceptor trap in the InGaN layer. A second resonance
with g≈1.99 is identified as a deep donor. 相似文献
15.
Growth of GaN on porous SiC and GaN substrates 总被引:1,自引:0,他引:1
C. K. Inoki T. S. Kuan C. D. Lee Ashutosh Sagar R. M. Feenstra D. D. Koleske D. J. Díaz P. W. Bohn I. Adesida 《Journal of Electronic Materials》2003,32(8):855-860
We have studied the growth of GaN on porous SiC and GaN substrates, employing both plasma-assisted molecular-beam epitaxy
(PAMBE) and metal-organic chemical-vapor deposition (MOCVD). For growth on porous SiC, transmission electron microscopy (TEM)
observations indicate that the epitaxial-GaN growth initiates primarily from surface areas between pores, and the exposed
surface pores tend to extend into GaN as open tubes and trap Ga droplets. The dislocation density in the GaN layers is similar
to, or slightly less than, that observed in layers grown on nonporous substrates. For the case of GaN growth on porous GaN,
the overgrown layer replicates the underlying dislocation structure (although considerable dislocation reduction can occur
as this overgrowth proceeds, independent of the presence of the porous layer). The GaN layers grown on a porous SiC substrate
were found to be mechanically more relaxed than those grown on nonporous substrates; electron-diffraction patterns indicate
that the former are free of misfit strain or are even in tension after cooling to room temperature. 相似文献
16.
Ki Seok Kim Sang‐Mook Kim Hyun Jeong Mun Seok Jeong Gun Young Jung 《Advanced functional materials》2010,20(7):1076-1082
The improvement of the light extraction efficiency (LEE) of a conventional InGaN blue light‐emitting diode (LED) by the incorporation of one‐dimensional ZnO sub‐microrods is reported. The LEE is improved by 31% through the wave‐guiding effect of ZnO sub‐microrods compared to LEDs without the sub‐microrods. Different types of ZnO microrods/sub‐microrods are produced using a simple non‐catalytic wet chemical growth method at a low temperature (90 °C) on an indium‐tin‐oxide (ITO) top contact layer with no seed layer. The crystal morphologies of needle‐like or flat‐top hexagonal structures, and the ZnO microrods/sub‐microrod density and size are easily modified by controlling the pH value and growth time. The wave‐guiding phenomenon within the ZnO rods is observed using confocal scanning electroluminescence microscopy and micro‐electroluminescence spectra. 相似文献
17.
Q. He H. Lin Y. Weng B. Zhang Z. Wang G. Lei L. Wang Y. Qiu F. Bai 《Advanced functional materials》2006,16(10):1343-1348
An organic compound with two triphenylamine moieties linked with binaphthyl at the 3,3′‐positions (2,2′‐dimethoxyl‐3,3′‐ di(phenyl‐4‐yl‐diphenyl‐amine)‐[1,1′]‐binaphthyl, TPA–BN–TPA) can be synthesized by Suzuki coupling. Amorphous and homogeneous films are obtained by either vacuum deposition or spin‐coating from solution in good solvents, while single crystals are grown in an appropriate polar solvent. X‐ray crystallography showed that a TPA–BN–TPA crystal is a multichannel structure containing solvent molecules in the channels. The intramolecular charge‐transfer state resulting from amino conjugation effects is observed by solvatochromic experiments. The high glass‐transition temperature (130 °C) and decomposition temperature (439 °C) of this material, in combination with its reversible oxidation property, make it a promising candidate as a hole‐transport material for light‐emitting diodes. With TPA–BN–TPA as the hole‐transporting layer in an indium tin oxide/TPA–BN–TPA/aluminum tris(8‐hydroxyquinoline)/Mg:Ag device, a brightness of about 10 100 cd m–2 at 15.6 V with a maximum efficiency of 3.85 cd A–1 is achieved, which is superior to a device with N,N′‐di(1‐naphthyl)‐N,N′‐diphenyl‐[1,1′‐biphenyl]‐4,4′‐diamine as the hole‐transporting layer under the same conditions. Other devices with TPA–BN–TPA as the blue‐light‐emitting layer or host for a blue dye emitter are also studied. 相似文献
18.
High-temperature characteristics of the metal/AlxGa1_xN/GaN M/S/S (M/S/S) diodes have been studied with current-voltage (I-V) and capacitance-voltage (C-V) measurements at high temperatures. Due to the presence of the piezoelectric polarization field and a quantum well at the AIxGa1_xN/GaN interface, the AIxGa1_xN/GaNdiodes show properties distinctly different from those of the AIxGa1_xN diodes. For the AIxGa1_xN/GaN diodes, an increase in temperature accompanies an increase in barrier height and a decrease in ideality factor, while the AIxGa1_xN diodes are opposite. Furthermore, at room temperature, both reverse leakage current and reverse break-down voltage are superior for the AIxGa1_xN/GaN diodes to those for the AIxGa1_xN diodes. 相似文献
19.
D. Aurongzeb D.Y. Song G. Kipshidze B. Yavich L. Nyakiti R. Lee J. Chaudhuri H. Temkin M. Holtz 《Journal of Electronic Materials》2008,37(8):1076-1081
We report experiments on the formation of GaN nanowires on epitaxial GaN using thin layers of Ni. GaN covered with Ni shows
roughening that is strongly dependent on the thickness of the Ni layer and the annealing conditions. With the initial Ni thickness
of 0.8 nm we observe formation of Ni-filled antidots. These act as nucleation sites in the growth of GaN nanowires, allowing
for the preparation of nanowires with an average diameter as small as 30 nm. Dense and well-oriented nanowires are formed
by pulsed metallorganic chemical vapor deposition at 750°C. The size of the Ni features determines the diameter of the GaN
nanowires, resulting in good control over the formation process. 相似文献