Graded Heterojunction of AlGaInP High-brightness Light Emitting Diodes

A simple model of the graded heterojunction in AlGaInP compound semiconductors was introduced to analyze the band profile. The band profiles are analyzed with the different grading ways but the same grading length and under the different doping densities. The effect of the different grading lengths on the surplus of the potential of the spike to the potential of N region are also analyzed under the different doping densities.Through the experiments,it proves that the performances of high brightness light emitting diodes can be improved by the effects of the graded heterojunction.     

Growth and properties of digitally-alloyed AlGaInP by solid source molecular beam epitaxy

Digital alloying using molecular beam epitaxy (MBE) was investigated to produce AlGaInP quaternary alloys for bandgap engineering useful in 600-nm band optoelectronic device applications. Alternating Ga_0.51In_0.49P/Al_0.51In_0.49P periodic layers ranging from 4.4 monolayers (ML) to 22.4 ML were used to generate 4,000-Å-thick (Al_0.5Ga_0.5)_0.51In_0.49P quaternary materials to understand material properties as a function of constituent superlattice layer thickness. High-resolution x-ray diffraction (XRD) analysis exhibited fine satellite peaks for all the samples confirming that digitally-alloyed (Al_0.5Ga_0.5)_0.51In_0.49P preserved high structural quality consistent with cross-sectional transmission electron microscopy (X-TEM) images. Low-temperature photoluminescence (PL) measurements showing a wide span of luminescence energies ～ 170 meV can be obtained from a set of identical composition digitally-alloyed (Al_0.5Ga_0.5)_0.51In_0.49P with different superlattice periods, indicating the bandgap tunability of this approach and its viability for III-P optoelectronic devices grown by MBE.     

AlGaInP发光二极管的全方位反射镜研究

全方位反射镜(ODR)AlGaInP发光二极管能够有效提高光提取效率。对全方位反射镜的设计及工艺进行优化:采用λ/4n厚的SiO2作为介质,光刻腐蚀导电孔,带胶保护,溅射AuZnAu,剥离后,再溅射300nmAu层,形成的ODR退火后在波长630nm处的反射率为72.1%,而单次溅射AuZnAu的反射率退火后为63.2%。实验结果说明新工艺满足了欧姆接触的需要,反射率提高了8.8%。     

The reliability of (AlxGa1−x)0.5In0.5P visible light‐emitting diodes

The reliability of AlGaInP double‐heterostructure (DH) light‐emitting diodes (LEDs) operating typically at 600 nm has been studied. To investigate degradation, accelerated aging at ambient temperatures of 50, 75 and 125°C has been carried out for over 5000 h. The activation energy of homogeneous degradation was determined to be 0.8 eV and an extrapolated half‐life in excess of 10⁶ h was estimated at an ambient temperature of 20°C. Copyright © 2000 John Wiley & Sons, Ltd.     

Hydrogen sensing characteristics of AlGaInP/InGaAs enhancement/depletion-mode co-integrated doping-channel field-effect transistors

In this article, the hydrogen sensing characteristics of Al_0.25Ga_0.25In_0.5P/In_0.1Ga_0.9As enhancement/depletion-mode co-integrated pseudomorphic doping-channel field-effect transistors by wet selectively etching process are demonstrated. At drain current of 0.1 mA/mm, the threshold voltages are of −0.97 (+0.6) V and −1.22 (+0.31) V in air and at hydrogen concentration of 9800 ppm, respectively, for the depletion (enhancement)-mode device. In addition, by employing the co-integrated FETs the transfer characteristics of the direct-coupled FET logic (DCFL) obviously vary under hydrogen ambience. The V_OH value reduces and the V_OL value increases in the DCFL with the measurement of hydrogen detection.     

红色AlGaInP激光器的特性及热特性分析

设计和制备了λ＝680nm的红色AlGaInP/GaInP应变量子阱激光器. 制得的未镀膜20μm脊型条形红色激光器的输出功率达到100mW,斜率效率0.56W/A,垂直和平行远场发散角分别为31°和9°. 未镀膜4m深腐蚀器件的功率可达10mW, 斜率效率为0.4W/A,峰值波长为681nm,峰值半宽为0.5nm. 不同腔长器件的特性显示器件的内损耗为4.27/cm,内量子效率达45%. 对不同腔长的器件进行了变温测试,得到器件的特征温度为120～190K.     

异常掺杂引起的AlGaInP同型结结构

用电化学C－V和I－V特性分析的方法,对Mg掺杂在MOCVD生长AlGaInP发光二极管（LED）的影响进行了研究。通过电化学C－V分析,确定了在生长结构中Mg掺杂从有源层到GaP窗口层由高到低的情况;用I－V特性分析的方法对器件结构进行了分析,发现了异常的实验结果。同时理论计算得到了同型结（N^ -N,P^ -P)的势垒高度和空间电荷区的宽度,由此得到了在同型结两侧浓度比不同时的差异,极好的解释了异常的I－V测试结果。     

晶片键合在AlGaInP发光二极管中的应用

(AlxGa1-x)0.5In0.5P高亮度发光二极管是在GaAs衬底上匹配外延的,它的外量子效率受限于吸收光线的GaAs衬底。LED晶片键合技术可以把LED外延片和GaP透明衬底、金属镜面衬底或蓝宝石衬底结合以提高出光效率。本文对上述三种晶片键合的器件制备过程和器件特点进行了描述。     

AlGaInP light-emitting diodes with SACNTs as current-spreading layer

Transparent conductive current-spreading layer is important for quantum efficiency and thermal performance of light-emitting diodes (LEDs). The increasing demand for tin-doped indium oxide (ITO) caused the price to greatly increase. Super-aligned carbon nanotubes (SACNTs) and Au-coated SACNTs as current-spreading layer were applied on AlGaInP LEDs. The LEDs with Au-coated SACNTs showed good current spreading effect. The voltage bias at 20 mA dropped about 0.15 V, and the optical power increased about 10% compared with the LEDs without SACNTs.