隧道结AlGaInP发光二极管

报道了通过隧道结将衬底的导电类型从n型转变到p型,从而可以利用n型GaP作为以n型GaAs为衬底的AlGaInP发光二极管的电流扩展层.n型电流扩展层的电阻率低于p型电流扩展层的电阻率,这种结构改善了电流扩展层的作用,从而提高了发光二极管的光提取效率.对3μm GaP电流扩展层的发光二极管,实验结果表明,隧道结发光二极管的发光功率与具有相同基本结构的传统发光二极管相比,20mA时发光功率提高了50%,100mA时提高了66.7%.     

隧道结AlGaInP发光二极管

报道了通过隧道结将衬底的导电类型从n型转变到p型,从而可以利用n型GaP作为以n型GaAs为衬底的AlGaInP发光二极管的电流扩展层.n型电流扩展层的电阻率低于p型电流扩展层的电阻率,这种结构改善了电流扩展层的作用,从而提高了发光二极管的光提取效率.对3μm GaP电流扩展层的发光二极管,实验结果表明,隧道结发光二极管的发光功率与具有相同基本结构的传统发光二极管相比,20mA时发光功率提高了50%,100mA时提高了66.7%.     

调制掺杂同型结对HB—LED工作电压的影响

根据电化学C－V测量AIGalnP外延片获得的载流子浓度深度分布数据,以及其LED外延片封装后的工作电压,计算了其中N^ －N与P^ －P两种同型结的接触电势差,指出调制掺杂同型结的掺杂浓度分布是影响LED 工作电压的另一大因素,并提出了进一步降低LED工作电压的有效措施。     

薄膜AlGaInP发光二极管中光子吸收的研究

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。     

AlGaInP橙色发光二极管的研制

利用ＬＰ－ＭＯＣＶＤ外延生长ＡｌＧａＩｎＰＤＨ橙色发光二极管，２０ｍＡ工作条件下发光波长峰值在６２８ｎｍ，ＦＷＨＭ为２６ｎｍ，１５°（２θ１／２）视角封装后亮度达到３１０ｍｃｄ；８０ｍＡ工作条件下亮度达到１０００ｍｃｄ。并且分析了生长过程中杂质向有源区扩散对发光光谱的影响。     

AlGaInP高亮度发光二极管

分析了ＡｌＧａＩｎＰ材料的特点和ＡｌＧａＩｎＰ高亮度发光二极管发光效率的决定因素,对目前国际上研究比较成熟的一些典型结构进行了综合分析,从理论上指出ＡｌＧａＩｎＰ发光二极管在橙黄波段的发光效率的最终决定因素是光的提取效率,而在黄绿波段是发光二极管的内量子效率。并利用ＬＰ－ＭＯＣＶＤ技术制备了ｃｄ级橙黄高亮度发光二极管,发光波长峰值在６０５ｎｍ,ＦＷＨＭ为１８．３ｎｍ,２０ｍＡ工作电流下,５．０８ｃｍ（２英寸）外延片管芯平均轴向发光强度为２０ｍｃｄ,最大３０ｍｃｄ,平均工作电压１．９Ｖ,透明峰值角度２θ１／２＝１５°时轴向发光强度达到１０００ｍｃｄ。     

GaAs基AlGaInP LED的研究和进展

探讨了GaAs基AlGaInP LED的最新研究与进展,介绍了AlGaInP红光LED外延材料的能带结构和基本的外延层结构以及限制外量子效率的问题,探讨了几种高效率的LED器件结构设计。着重介绍了目前一些外量子效率比较高的LED器件的制作方法以及一些提高外量子效率的AlGaInP LED器件结构,最后探讨了AlGaInP LED在作为固体光源发展过程中仍然需要面对的挑战。     

AlGaInP红,橙,黄光高亮度LED外延材料

采用金属有机化合物汽相沉积技术生长用于高亮度发光管（ＵＢ－ＬＥＤ）的ＡｌＧａＩｎＰ／ＧａＡｓ半导体微结构材料，突破了材料结构设计和材料生长工艺的关键技术，生长出满足于Ｃｄ级的红、橙、黄光ＬＥＤ器件的外延材料。     

薄膜AlGaInP发光二极管中不同反光镜的研究

本文计算了GaP/Au 反光镜, GaP/SiO2/Au 三层ODR and GaP/ITO/Au 三层ODR的反射率随角度的变化值。制作了GaAs衬底的AlGaInP LED,Au反光镜、SiO2 ODR和ITO ODR的薄膜AlGaInP LED。在20mA下,四种样品光输出功率分别为1.04mW, 1.14mW, 2.53mW and 2.15mW。制作工艺退火后,Au扩散使Au/GaP反光镜的反射率降至9％。1/4波长的ITO和SiO2透射率不同造成了两种薄膜LED光输出功率不同。ITO ODR中加入Zn可以大大降低LED的电压,但并不影响LED的光输出。     

P-AlInP限制层掺杂对AlGaInP红光LED发光亮度影响

针对四元系AlGaInP红光发光二极管在制备过程中,材料的掺杂特性对于器件性能影响巨大,尤其是AlInP限制层材料的掺杂,对于器件光电性能具有明显的影响。在实际生产过程中P型掺杂浓度的波动非常大,明显影响到红光LED的发光均匀性。从不同的AlInP限制层P型掺杂浓度与LED发光亮度的关系入手,探索研究AlInP限制层P型掺杂浓度对LED发光亮度影响的规律,所得研究结果对于LED的器件结构设计以及MOCVD外延材料生长有一定的指导意义。     

Pure‐Red Dye for Organic Electroluminescent Devices: Bis‐Condensed DCM Derivatives

In this paper, the bis‐condensed 4‐(dicyanomethylene)‐2‐methyl‐6‐[p‐(dimethylamino)styryl]‐4H‐pyran ( DCM) derivatives are introduced as a new class of red dye for organic light‐emitting devices (OLEDs). They showed more red‐shifted emission than the mono‐substituted DCM derivatives and the emission maxima increased as the electron‐donating ability of the aromatic donor group increased. On the basis of these results, red light‐emitting devices were fabricated with bis‐condensed DCM derivatives as red dopants. For a device of configuration ITO/TPD/Alq₃ + DADB (5.2 wt.‐%)/Alq₃/Al (where ITO is indium tin oxide, TPD is N,N′‐diphenyl‐N,N′‐bis(3‐methylphenyl)‐1,1′‐biphenyl‐4,4′‐diamine, Alq₃ is tris(8‐hydroxyquinoline) aluminum, and DADB is [2,6‐bis[2‐[5‐(dibutylamino)phenyl]vinyl]‐4H‐pyran‐4‐ylidene]propanedinitrile), pure red emission was observed with Commission Internationale de l’Eclairage (CIE 1931) coordinates of (0.658, 0.337) at 25 mA/cm².     

Fine‐Tuning of Yellow or Red Photo‐ and Electroluminescence of Functional Difluoro‐boradiazaindacene Films

The present work describes the synthesis of difluoro‐boradiazaindacenes (Bodipy) functionalized at the central 8‐position by phenylamino moieties easily transformable into phenyl amide scaffoldings. Molecules carrying three linear or branched chains were prepared and characterized. An X‐ray crystal structure for the pivotal trimethoxyphenyl‐Bodipy derivative was determined, and the packing is discussed in terms of molecular interactions; a key feature for the formation of thin films. All of the dyes are thermally stable up to 170 °C but no liquid‐crystalline phases are observed. Reversible reduction and oxidation processes occur around +0.97 and −1.34 V, respectively, versus saturated calomel electrode in solution and the electroactivity and photoluminescence are maintained in thin films produced by vacuum evaporation. Interestingly, two distinct emissions are observed at 550 and 635 nm by electroluminescence of the trimethoxyphenyl‐Bodipy derivative, corresponding to the luminescence of isolated molecules and dimers, respectively. Doping Alq₃ films with this Bodipy molecule by vacuum evaporation produces organic light‐emitting diodes (OLEDs) in which very efficient energy transfer from the Alq₃ matrix to the Bodipy occurs by a resonance mechanism involving the first Bodipy excited state. Yellow light (550 nm, 344 cd m⁻² at 15 V) is emitted at low doping concentration (7 mol %), whereas red light (635 nm, 125 cd m⁻² at 15 V) is emitted at higher concentration (19 mol %). Dispersion of the Bodipy into a fluorescent poly(N‐vinylcarbazole) polymer (PVK) (≈3 mol % per repeating unit of PVK) by solution processing exclusively produces yellow emission owing to the isolated Bodipyfluorophore (550 nm, 213 cd m⁻² at 15 V). The second excited state of the Bodipy dye is likely involved during energy transfer from the PVK matrix.     

面向可见光通信的硅基InGaN/GaN多量子阱多口分路器光子集成芯片

为研究面向可见光通信的多功能光子集成芯片,实现可见光信号发射、探测、传输和功率分配的一体化的复合功能,该文提出一种基于硅基InGaN/GaN多量子阱材料的微型发光二极管(LED)多口分路器结构的光子集成芯片,对集成芯片进行了形貌、光电特性和可见光通信测试等多方面表征,实现了对可见光信号的有效传输和不同比例的多口功率分路,并对分路器不同端口的出射光强进行量化处理,最后,利用信号发生器在微型LED光源发射端加载300 kHz的矩形波电信号,收集分路器末端发射的调制可见光信号,输入/接收信号的波形变化趋势一致,说明该光子集成芯片可实现有效的可见光通信。该研究的主要目的是尝试性将可见光波段的光源和光电探测器集成在氮化物晶圆上,为可见光通信的全光网络的可见光信号片上集成式处理提供新的研究思路和方案,为发展面向可见光通信网络需求的复合功能光子集成芯片终端提供了更多可能性。     

透明导电ITO欧姆接触的AlGaInP薄膜发光二极管

提出了一种透明导电氧化铟锡(ITO)欧姆接触的AlGaInP薄膜发光二极管(LED)的结构和制作工艺.在这个结构里,ITO还作为窗口层材料,增强电流扩展,并应用了高反射率的金属作为反光镜.用Au-Sn合金(Au∶Sn＝8∶2,重量比)作为焊料,把带有金属反光镜的AlGaInP LED(RS-LED)外延片倒装键合到GaAs基板上,并去掉外延GaAs衬底,把被GaAs衬底吸收的光反射出去.与常规AlGaInP吸收衬底LEDs(AS-LED)和带有分布布拉格反光镜(DBR)的AlGaInP吸收衬底LEDs(DBR-AS-LED)电、光特性的比较,用透明导电ITO做欧姆接触的AlGaInP薄膜RS-LED结构能极大提高光输出功率和发光强度.正向电流20 mA时,RS-LED的光输出功率分别是AS-LED和DBR-AS-LED的2.4倍和1.7倍;RS-LED 20 mA下峰值波长624 nm的轴向光强达到了179.6 mcd,分别是AS-LED 20 mA下峰值波长627 nm和DBR-AS-LED 20 mA下峰值波长623 nm轴向光强的2.2倍和1.3倍.     

LED芯片脏污与几种芯片工艺现象的辩识

文章介绍了几种常见的LED芯片表面脏污类别以及预防对策,包括芯片制造商生产过程中产生和封装厂生产中带入的脏污,另外列举了几种与脏污容易混淆的芯片工艺异常规象。     

Water bonding of 50-mm-diameter mirror substrates to AlGaInP light-emitting diode wafers

The feasibility of bonding 50-mm-diameter Si with a Au/AuBe mirror to AlGaInP light-emitting diode (LED) wafers is demonstrated. Wafer bonding over the entire wafer area is achieved while the metallic mirror still maintains high reflectivity. Using this technique, the mirror-substrate AlGaInP LEDs are fabricated across an entire 50-mm wafer. The test data show that 98% of the dice with operating voltages <2.2 V at 20 mA and 85% of the dice with luminous intensity in the 130∼140 mcd region. The wafer-bonded mirror-substrate LED lamps operating at 626 nm can emit 3 lm at 20 mA with a forward voltage of 2 V, corresponding to a luminous efficiency of 74 lm/W. Moreover, they present a peak power efficiency of 21% with 4 mW output at 10 mA (1.9 V). Essentially no degradation is observed for these LEDs after 2000 h stress at 80°C and 50 mA (55.6 A/cm²). The results indicate the mirror-substrate AlGaInP LEDs of highly reliable and efficient performance.     

LED灯失效的几种常见原因分析

本文基于LED发光二极管的工作原理、制程,找出了LED单灯失效的几种常见原因,并阐述了在材料、生产过程、应用等环节如何预防和改善的对策。