2～4μm波长的InAsPSb异质结激光管材料的液相外延

采用液相外延方法,生长出外延层与衬底之间的失配度△α/α≤1.6×10-3界面平直、组分恒定的InAsPSb/InAs外延晶体.单异质结外延层,得到了3.09μm波长的激光输出,双异质结外延片也得到了较好的伏-安特性曲线.     

p型Ga0.47In0.53AS接触层的生长

用过冷法在632-630℃生长了掺Zn的p型Ga0.47In0.53As接触层.研究了液相中Ga组分和Zn组分对GaxIn1-xAs/InP异质结晶格失配的影响,用一次外延技术生长了GaxIn1-xAs作接触层的GaInAsP/InP双异质结.     

双结多色发光二极管

——在GaAs:Si—GaAsP异质结基片上涂复NaYF_4:Yb,Er磷光体,已经研制出具有多色性能的发光二极管。这种双结单个管芯的发光二极管,其绿光和红光强度具有中心对称分布。调整磷光体厚度,可以得到介于绿光和红光之间的中间光色。在电流密度30A/cm~2的情况下,每种颜色光的亮度都高于100 fL,绿光的功率转换效率为 2—3×10~(-4)。对于单个GaAs:Si发光二极管,由于红外光在 GaAsP层中的折射,在20A/cm~2时,亮度低于250fL。     

锗硅/硅异质结材料的化学气相淀积生长动力学模型

基于化学气相淀积(CVD)的Grove理论和Fick第一定律,提出并建立了锗硅(SiGe)/硅(Si)异质结材料减压化学气相淀积(RPCVD)生长动力学模型.与以前锗硅/硅异质结材料生长动力学模型仅考虑表面反应控制不同,本模型同时考虑了表面反应和气相传输两种控制机理,并给出了两种控制机理极限情况下的模型.本模型不仅适用于低温锗硅/硅应变异质结材料生长的表征,也适用于表征高温锗硅/硅弛豫异质结材料生长的表征.将模型计算值与实验结果进行了对比,无论是625℃低温下的应变SiGe的生长,还是900℃高温下的弛豫 关键词： SiGe/Si异质结材料 化学气相淀积生长动力学模型 Grove理论 Fick第一定律     

硅基混合集成技术的研究进展

硅基光电子集成技术(PICs)为高速宽带光互连和光通信的发展提供了一种低成本的有效方案,受到人们的高度重视.目前将III-V族和锗等半导体化合物集成到硅衬底的方法主要分为两类:异质结外延生长和异质材料的键合.低温下晶片键合的方法克服了异质结外延生长中的生长温度高、晶格失配和材料热膨胀系数非共容性的缺点,为大规模的异质(不同半导体材料)集成提供了可能.文章综述了近几年来一些常用的键合方法,并对低温键合方法的发展动向做了展望.     

pn结电容-电压法测量应变SiGe禁带宽度

利用应变SiGe/Si异质pn结电容-电压（C-V）特性确定SiGe禁带宽度的技术.该技术根据SiGe/Si异质pn结C-V实验曲线，计算出 pn结接触电势差，并得到SiGe/Si的价带偏移量和导带偏移量，进而求得SiGe禁带宽度.该技术测试方法简便，其过程物理意义清晰，既适用于分立的SiGe/Si异质pn结，也可直接分析SiGe/Si异质结器件中的SiGe 禁带宽度.实验结果与理论计算及其他相关文献报道的结果符合较好. 关键词： SiGe/Si 异质pn结 C-V 禁带宽度     

磷烯基二维范德瓦尔斯异质结的理论表征（英文）

本文基于单层黑磷和蓝磷,理论设计出二维范德瓦尔斯异质结、能带结构、态密度、Bader电荷布局、电荷密度差分图及光吸收谱等,计算结果表明它是典型的第二型异质结,有利于光生载流子分离,且可见光捕获能力显著增强.内禀的界面极化电场能有效阻止光生电子-空穴的复合.表明磷烯基二维范德瓦尔斯异质结是一类性能优异的光解水催化剂.     

磷烯基二维范德瓦尔斯异质结的理论表征

本文基于单层黑磷和蓝磷,理论设计出二维范德瓦尔斯异质结、能带结构、态密度、Bader电荷布局、电荷密度差分图及光吸收谱等,计算结果表明它是典型的第二型异质结,有利于光生载流子分离,且可见光捕获能力显著增强.内禀的界面极化电场能有效阻止光生电子-空穴的复合.表明磷烯基二维范德瓦尔斯异质结是一类性能优异的光解水催化剂.     

La1/8Ca7/8MnO3/Sr0.95Nb0.05TiO3异质结的整流特性和磁输运性质

在5%Nb掺杂的SrTiO3衬底上用磁控溅射法外延生长了La1/aCa7/aMnO3薄膜形成异质结,该异质结有类似于传统P-n结的整流特性.磁场下扩散电压减小,当温度低于130 K以下,扩散电压的减小非常明显.这和在此温度以下,La1/8Ca7/aMnO3出现自旋倾斜态密切相关.我们计算出异质结的结电阻和磁致电阻(MR),在不同大小的正负偏压,不同磁场下,都得到负的MR值.我们给出界面附近的La1/8Ca7/8MnO3的能带结构并分析了外加磁场对洪德耦合,Jahn-Teller畸变等机制的作用,来解释该异质结的磁输运行为.结果有助于了解高Ca掺杂锰氧化物异质结的性质.     

ZnO/Si异质结的光电转换特性研究

利用直流反应溅射方法在p型Si衬底上生长掺Al的n型ZnO薄膜,测量了由n型ZnO薄膜和p型Si衬底组成的异质结在黑暗和光照条件下的I-V特性,结果表明该异质结具有优良的整流特性,而且在光照条件下的反向电流迅速增大并很快趋于饱和.通过测量ZnO薄膜的光电流和异质结的光电压的光谱响应,初步分析了异质结的光电转换机理.测量结果显示,在入射光波长为380nm时光电流强度明显下降,反映出光电流与ZnO薄膜禁带宽度的密切关系;同时还发现,在与ZnO禁带宽度相对应的波长前后所产生的光生电压方向相反.推测这一现象与异质结的能带结构密切相关. 关键词： ZnO薄膜 异质结 光电转换 光谱响应     

大功率全方位反射镜发光二极管性能研究

在现有工艺条件下通过简单工艺实现大功率GaN基多量子阱全方位反射镜(ODR)发光二极管(LED)的研制,并对试制LED样品进行了光学、电学和色参数三个方面性能测试.测试结果发现,ODR芯片比普通芯片的光强提高了244 mcd,极大提高了发光强度;ODR LED光通量、光效、色纯度比普通LED分别提高了6.04%,5.74%,78.64%.ODR LED具有绝对优势是其色温要比普通LED的色温低1804 K,明显改善大功率LED的色温缺陷. 关键词： 发光二极管 ODR 色温     

Curing of dental composites by use of InGaN light-emitting diodes

A potential application of blue-light-emitting InGaN LED's as a polymerizing source for dental composite materials is described. We compared a basic LED device with a conventional curing light in vitro to determine the polymerization parameters and to examine the effect of the curing process on the physical properties of these materials. It was determined that an array of six LED's was able to set a range of composite materials more quickly than a conventional light source, with the cured compounds showing similar hardness and material shrinkage parameters but with a lower material temperature rise during the curing process using the array. These findings indicate that a device consisting of several InGaN LED's would be an effective instrument for curing certain light-sensitive materials, particularly dental composites.     

Non-exponential dark capacitance transients from red-emitting GaP LED's — Field and edge effects on the 0.75 eV centre

The origin of the non-exponential behaviour of the previously reported [2] dark capacitance transients from red-emitting GaP LED's has been investigated in detail. In particular, the effects of the electric field and the junction edge-region on hole-emission from the 0.75 eV level has been studied. A small apparent electric-field enhancement of the emission rate has been shown to be caused predominantly by junction edge effects.     

绿光LED激发荧光的研究

介绍了绿光LED作为荧光激发光源的可行性。使用波长为 5 30nm的超高亮度绿光LED对荧光物质四氯四溴荧光素 (C2 0 H2 Br4 Cl4 Na2 O5)的荧光发射进行了研究。设计了小巧的荧光液池 ,将四个LED分别安置于液池侧面 ,聚光后的光束交汇于液池中同一位置以提高激发光的强度 ;使用 1kHz方波调制LED ,运用分光光度计方法 ,接收到波长为 5 70nm的荧光信号     

SiC材料及器件研制的进展

作为第三代的半导体材料－ＳｉＣ具有禁带宽度大、热导率高、电子的饱和漂移速度大、临界击穿电场高和介电常数低等特点,在高频、大功率、耐高温、抗辐照的半民体器件及紫外探测器和短波发光二级管等方面具有广泛的应用前景,文章综述了半导体ＳｉＣ材料生长及其器件研制的概况。     

大功率白光LED恒压驱动与恒流驱动下温度特性的实时测量

采用贴片pt100设计一种快响应温度计,在恒压和恒流驱动下分别实时测量大功率白光LED温度对光电参数的影响,测量误差小、效率高.实验表明,LED在恒压驱动时电流和光强随温度的升高而增大,而在恒流驱动时光强随温度的升高而减小;发光效率在恒流和恒压驱动时均随温度的升高而降低,但前者影响较小.     

Two-photon optical-beam-induced current imaging of indium gallium nitride blue light-emitting diodes

Epilayers of packaged indium gallium nitride light-emitting diodes (LED's) are characterized by optical-beam-induced current (OBIC) and photoluminescence laser-scanning microscopy through two-photon excitation. Light scattering and absorption in the packaging material and the p-doped top layer of the LED's are greatly reduced as a result of employing a longer excitation wavelength, with energy that is less than the bandgap of the top p layer. Compared with single-photon OBIC, two-photon OBIC imaging not only exhibits superior image quality but also reveals more clearly the characteristics of the epilayers that are being focused on.     

Wideband deep penetration of photon-number fluctuations into the quantum regime in series-coupled light-emitting diodes

Experimental results on the squeezing of photon-number fluctuations of series-coupled LED's driven by a constant-voltage source are presented that illustrate the advantage of series-coupled LED's, namely, a greater squeezing capability than that of a single LED driven through an equivalent series resistor. We discuss the microscopic origin of the deep squeezing on the basis of quantum-mechanical Langevin equations.     

AlGaInP-Si glue bonded high performance light emitting diodes

We propose a new method of using conductive glue to agglutinate GaAs based AlGaInP light emitting diodes (LEDs) onto silicon substrate,and the absorbing GaAs layer is subsequently removed by grinding and selective wet etching.It was found that AlGaInP-Si glue agglutinated LEDs have larger saturation current and luminous intensity than the conventional LEDs working at the same injected current.The luminous intensity of the new device is as much as 1007.4 mcd at a saturation current of 125 mA without being encapsulated,while the conventional LEDs only have 266.2 mcd at a saturation current of 105 mA.The luminescence intensity is also found to increase by about 3.2% after working at 50 mA for 768 h.This means that the new structured LEDs have good reliability performance.     

负反馈提高高阻恒流源驱动的LED的输出光场噪声压缩量

研究高阻恒流源驱动的ＬＥＤ所发射光场的粒子数噪声压缩与ＬＥＤ电、光量子效率，漏电流效应，光子流涨落负反馈及噪声频率的关系。指出：在高阻恒流ＬＥＤ中引入适量光子流涨落负反馈能产生粒子数压缩态光场并极大地提高粒子数噪声压缩，其理想压缩仅受限于高阻恒流源残余噪声、ＬＥＤ漏电流效应和量子效率。 关键词：