半导体蓝绿激光器的发展现状

近年来皮长半导体绿激光器的取得了引人瞩目的进展。文章介绍了利用ＺｎＳｅ和ＧａＮ两大材料轩蓝绿激光器必须解决的关键技术问题。以及蓝绿半导体激光器目前的发展现状。     

GaN器件的某些关键工艺及其进展

自９０年代初，在ＧａＮ材料的ｐ型掺杂和异质外延技术取得突破性进展之后，ＧａＮ的区姆接触及腐蚀技术就成为ＧａＮ器件向商品化发展的关键工艺。本文论术了ＧａＮ的欧姆接触和腐蚀工艺的研究现状。     

GaN器件的某些关键工艺及其进展

自９０年代初，在ＧａＮ材料的ｐ型掺杂和异质外延技术取得突破性进展之后，ＧａＮ的欧姆接触及腐蚀技术就成为ＧａＮ器件向商品化发展的关键工艺。近年来，在这些领域的研究论文逐年增多，已形成了一股研究热潮。本文论述了ＧａＮ的欧姆接触和腐蚀工艺的研究现状。     

GaN薄膜技术的几点突破

简单回顾了半导体短波长激光器的发展过程,归纳了ＧａＮ基ＬＤ（激光器）制作中ＧａＮ膜的几点技术突破。     

高亮度GaN系蓝色发光二极管

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。     

SiC促进了兰光LED的发展

第三代宽带隙材料对光电子学的影响最大。其中某些技术有力地推动了大功率芯片—硅双极,硅ＭＯＳＦＥＴ以及宽带隙器件(兰光ＬＥＤ)和ＧａＮ激光器。由于曾经寄予希望的硒化锌状况令人失望,ＧａＮ就成了唯一的选择,ＧａＮ的短波长(410ｎｍ)使其数据存储容量4倍于ＧａＮｓ器件。尽管已经决定采用ＧａＮ基做有源区,但衬底材料的选择仍然犹豫未决:用兰宝石还是碳化硅。兰宝石已被著名的Ｎｉｃｈｉａ化学公司和ＨｅｗｌｅｔｔＰａｃｋｏｒｄ公司成功地用作衬底。Ｎｉｃｈｉａ公司制成的兰光激光器的寿命在20℃达10000小时,在50℃下降低到1000小…     

在室温下量子点发射稳定的1.3μm光

日本富士通实验室的研究人员描述了如何制造在室温下可发射１．３μｍ光的量子点激光器。这种由ＩｎＧａＮ／ＧａＮ组成的量子点是由分子束外延生长而成．这种边缘类型的激光器有一个２～３ｘ１０１０／ｃｍ２的量子点密度,这个数值两倍于以前报道的,并具有９００μｍ的腔长．一个最优化的生长速率及一个覆盖在量子点上的ＩｎＧａＮ＃层保证了这个高量子点密度。为了提高输出,研究人员用三层量子点堆积来构造激光器。２５℃时器件的阈值电流为８ｍＡ。研究人员确信低阈值电流是由于高量子点密度及多重量子点层引起,二者都对光学增益有贡…     

MOCVD生长的InGaN／GaN双异质结构LED的生长和表征

我们在ｃ面蓝宝石上用常压ＭＯＣＶＤ法得到了高质量ＩｎＧａＮ外延层。研究表明，Ｉｎ分凝系数不仅与生长温度有关，而且与ＩｎＧａＮ薄膜的生长速度有关。观测到了在生长温度低至７００℃，Ｉｎ摩尔分数达０．２０时生长的ＩｎＧａＮ膜的强烈的能带边缘光致发光。本文还介绍了有关蓝光ＩｎＧａＮ／ＧａＮ双异质结构ＬＥＤ所取得的最初结构。     

大功率半导体激光器的发展现状

介绍了无铝激光器、宽波导激光器、展宽条形激光器及其它类型激光器（如低限制激光器）、ＧａＮ基激光器和分布反馈激光器的发展现状     

光电导及光反射法测量AlGaN薄膜的Al组分

ＡｌＧａＮ／ＧａＮ异质结兰光激光器和发光管近年来得到很大的发展．高速和高功率的ＡｌＧａＮ／ＧａＮ异质结场效应管（ＨＦＥＴ）的研究也得到很大的重视．ＡｌＧａＮ 薄层中的Ａｌ组分是决定此类器件的设计和性能的一个重要参量． 传统的测量组分的方法如ＸＰＳ和Ａｕｇｅｒ等方法需要大型的仪器,而且大多数方法是破坏性的,注意到ＡｌＧａＮ的禁带宽度Ｅｇ和Ａｌ组分有直接的关系,可以通过光学方法先测出Ｅｇ,用下式推算出Ａｌ的组分： Ｅｇ（ＡｌＧａＮ）＝ Ｅｇ（ＧａＮ）（１－ｘ）＋Ｅｇ（ＡｌＮ）ｘ－ｂｘ（１－ｘ）．其中ｘ是…     

GaN基和GaAs基半导体激光器的电学特性研究

介绍了一种能够全面表征半导体二极管器件的电学特性的方法,此方法结合半导体二极管的正向交流特性和直流特性,称之为正向交流小信号法。利用该方法深入地研究和对比分析了GaN基和GaAs基半导体激光器的电学特性,包括表观电容、串联电阻和理想因子。实验结果表明,对于GaN基和GaAs基半导体激光器,其开始发光的过程同步于其电容由正转变为负的过程。进一步实验结果表明,GaN基半导体激光器比GaAs基半导体激光器具有更大的串联电阻和更大的理想因子。这是由于GaN基激光器的器件工艺不够完善以及外延生长的GaN材料具有很大的位错密度。该研究为提高和改善GaN基激光器的性能提供了必要的依据以及理论指导。     

对GaAs衬底表面进行氩离子清洗的研究

介绍了离子清洗技术在提高980nm半导体激光器可靠性方面的应用。外延片在空气中解理后，半导体激光器的腔面会吸附上碳和氧等杂质。腔面吸附的氧和碳严重影响了器件的可靠性。本文用GaAs衬底表面模拟半导体激光器的解理腔面，并对其进行氩离子清洗，俄歇电子能谱（AES）分析显示氩离子清洗可以有效地清除GaAS表面的氧和碳等杂质。     

GaN基半导体激光器发展动态研究

简单介绍了材料特性及器件应用 ,着重介绍了氮化镓基半导体激光器的研究进展及其关键技术。     

The effect of bonding wires on longitudinal temperature profiles oflaser diodes

The thermal effect of bonding wires in laser diodes is analyzed using the analytical temperature solution for a five-layer structure and an iteration technique. Finite element method is used to confirm the results. Due to the bonding wire, the longitudinal temperature profile of laser diodes exhibits significant reduction at the foot of the wire even with uniform longitudinal heat distribution. For lasers designed with uniform longitudinal current density, heat increases toward the laser facets because of nonradiative recombination of carriers through surface quantum states on the facets. This leads to local temperature concentration on and near the facets. The conduction of heat through the bonding wire at the top center of laser chips further enhances this temperature concentration. In use, the stripe electrode of laser diodes is at uniform voltage. Under this operation condition, the current density would increase in the higher temperature regions due to bandgap decrease, causing higher heat flux. And consequently even higher temperature. Accordingly, the location of bonding wire and the shape of stripe electrode require careful consideration in the design phase to achieve uniform longitudinal temperature profile     

GaN基蓝紫光激光器的材料生长和器件研制

报道了国内首次研制成功的GaN基蓝紫光激光器的材料外延生长、器件工艺和特性.用MOCVD生长了高质量的GaN及其量子阱异质结材料,以及异质结分别限制量子阱激光器结构材料.GaN材料的X射线双晶衍射摇摆曲线(0002)对称衍射和(10(-1)2)斜对称衍射半宽分别为180″和185″;3μm厚GaN薄膜室温电子迁移率达到850cm2/(V·s).基于以上材料,分别成功研制了室温脉冲激射增益波导和脊型波导激光器,阈值电流密度分别为50和5kA/cm2,激光发射波长为405.9nm,脊型波导结构激光器输出光功率大于100mW.     

Visible fiber lasers excited by GaN laser diodes

This paper describes and discusses visible fiber lasers that are excited by GaN laser diodes. One of the attractive points of visible light is that the human eye is sensitive to it between 400 and 700 nm, and therefore we can see applications in display technology. Of course, many other applications exist. First, we briefly review previously developed visible lasers in the gas, liquid, and solid-state phases and describe the history of primary solid-state visible laser research by focusing on rare-earth doped fluoride media, including glasses and crystals, to clarify the differences and the merits of primary solid-state visible lasers. We also demonstrate over 1 W operation of a Pr:WPFG fiber laser due to high-power GaN laser diodes and low-loss optical fibers (0.1 dB/m) made by waterproof fluoride glasses. This new optical fiber glass is based on an AlF₃ system fluoride glass, and its waterproof property is much better than the well known fluoride glass of ZBLAN.     

Pulsed semiconductor lasers with higher optical strength of cavity output mirrors

Asymmetric heterostructures with an ultrathick waveguide based on an AlGaAs/GaAs alloy system that allow lasing at a wavelength of 905 nm have been developed and fabricated by hydride metalorganic vapor-phase epitaxy. The internal optical loss and internal quantum efficiency of semiconductor lasers based on such structures were 0.7 cm^-1 and 97%, respectively. It is shown that the highest output optical power of laser diodes with antireflecting (SiO₂) and reflecting (Si/SiO₂) coatings deposited on untreated Fabry-Perot cavity facets obtained by cleaving in an oxygen atmosphere reached 67 W in the pulsed mode and is limited by mirror damage. Treatment of Fabry-Perot cavity facets by etching in argon plasma and the formation of coatings with passivating and oxygen-blocking GaN and Si₃N₄ layers allowed an increase in the maximum output optical power to 120 W. Mirror damage was not observed at the attained output optical power.     

脊形结构GaN蓝光激光器的热模拟分析

利用二维热传导模型分析了GaN激光器的温度特性.计算了有源区在连续工作条件下的最大温升,分析了激光器工作时的功率密度和p电极比接触电阻率等参数对温度特性的影响.模拟结果表明,采用不同衬底和不同装配形式对器件温度特性的影响很大,正装形式下,窄的脊形条宽能提高器件的高温工作稳定性.     

980nm半导体激光器长期老化结果及失效分析

为了提高980nm半导体激光器的可靠性,采用氦离子注入形成腔面电流非注入区技术制作了4μm条宽的脊形波导激光器,并利用同一块外延片制作了常规工艺的4μm脊形波导激光器作为对比。经过长期老化实验得知:常规工艺器件在1500h前全部失效,而采取新技术的器件寿命超过了3000h。通过对器件的扫描电镜分析发现,腔面灾变性损伤、铟焊料的质量和腔面污染等因素对器件失效有直接影响。     

High-power and long-lifetime inGaN blue- violet laser diodes grown by molecular beam epitaxy

InGaN 405 nm multiple quantum well laser diodes grown by molecular beam epitaxy (MBE) with a continuous-wave (CW) lifetime of up to 42 h are reported. The CW threshold current density of the ridge waveguide laser diodes is 3.6 kA/cm² and the slope efficiency for uncoated facets is 0.42 W/A per facet with a maximum CW output power of 45 mW per facet. Statistical variation of CW lifetime with dissipated power is presented for MBE-grown laser diodes from five different wafers.