使用SiO2介质膜实现InGaAsP量子阱混杂

报道了使用SiO2介质膜导致的无杂质空位扩散实现InGaAsP多量子阱混杂的实验,得到200nm的最大带隙波长蓝移.另外,采用量子阱混杂制作了蓝移的FP腔激光器,其性能与未混杂的激光器相当.     

多变量离子注入型量子阱混杂效应

为实现InP基单片集成光电子器件和系统,对InGaAsP/InGaAsP分别限制异质结多量子阱激光器结构展开量子阱混杂(QWI)技术研究。在不同能量P离子注入、不同快速热退火(RTA)条件以及循环退火下,研究了有源区量子阱混杂技术,实验结果采用光致发光(PL)谱进行表征。实验结果表明:在不同变量下皆可获得量子阱混杂效果,其中退火温度影响最为显著,且循环退火可进一步提高量子阱混杂效果;PL谱蓝移随着退火温度、退火时间和注入能量的增大而增大,退火温度对蓝移的影响最大,在注入剂量为1×10^14 ion/cm2,注入能量为600keV,750℃二次退火150s时获得最大蓝移量116nm。研究结果为未来基于QWI技术设计和制备单片集成光电子器件和系统奠定了基础。     

基于无杂质空位混杂法制备带有无吸收窗口的940nm GaInP/GaAsP/GaInAs半导体激光器研究

为提高940nm半导体激光器抗灾变性光学损伤(COD)能力,采用无杂质空位量子阱混杂技术制备了带有无吸收窗口的940nm GaInP/GaAsP/GaInAs半导体激光器。借助光致发光光谱分析了退火温度和介质膜厚度对GaInP/GaAsP/GaInAs单量子阱混杂的影响;通过电化学电容-电压(EC-V)方法检测了经高温退火后激光器外延片的掺杂浓度分布的变化情况。实验发现,在875℃快速热退火条件下,带有磁控溅射法制备的200nm厚的SiO2盖层样品发生蓝移达29.8nm,而电子束蒸发法制备的200nm厚TiO2样品在相同退火条件下蓝移量仅为4.3nm。两种方法分别对蓝移起到很好的促进和抑制作用。将优化后的条件用于带有窗口结构的激光器器件制备,其抗COD能力提高了1.6倍。     

基于循环退火技术的InGaAs/AlGaAs量子阱混杂

为了解决由于激光器腔面处的光吸收引起的腔面光学灾变损伤(COD),采用无杂质空位扩散(IFVD)法,研究了由SiO2电介质层诱导的InGaAs/AlGaAs量子阱结构的带隙蓝移。使用等离子化学气相沉积(PECVD)在InGaAs/AlGaAs量子阱的表面生长SiO2电介质层;然后采用IFVD在N2环境下进行高温退火实验,从而实现量子阱混杂(QWI)。实验结果表明:蓝移量的大小随退火时间和电介质层厚度的变化而变化,样品覆盖的电介质层越厚,在相同的退火温度下承受的退火时间越长,得到的蓝移量也越大。然而,在高温退火中的时间相对较长时,退火对量子阱造成的损坏相当大。高温短时循环退火,能够在保护量子阱晶体质量的同时实现QWI。通过在850℃退火6min下循环退火5次,得到了46nm的PL蓝移,且PL峰值保持在原样品的80%以上。     

二氧化硅覆盖退火增强磷化铟基体激光器材料的量子阱混合

我们对SiO2覆盖退火增强InGaAs/InGaAsP/InP激光器材料量子阱混合技术进行了实验研究.相对于原始样品,退火时无SiO2覆盖的样品经800℃,30s快速退火后,其光致发光谱的峰值波长“蓝移”了7nm,退火时有SiO2覆盖的样品经过同样的快速退火后,其光致发光谱的峰值波长“蓝移”了56nm.即在同一片子上实现了在需要量子阱混合的区域带隙的“蓝移”足够大的同时,不希望量子阱混合的区域能带结构的变化创记录的小.本文认为增大量子阱的宽度、采用无应力的量子阱结构以及引入足够厚的缓冲层可以改善量子阱材料的晶格质量,有利于提高量子阱混合技术的可靠性与重复性,     

GaAsSb/GaAs量子阱激光器结构的发光研究

研究了GaAsSb/GaAs应变量子阱及应变补偿量子阱激光器结构的光致发光和电注入发光.结果表明,分子束外延生长温度的改变使量子阱发光性能发生系统性变化,证明生长温度对量子阱中锑的组分和界面质量具有重要影响. 同时,低温光致发光峰的波长随激发功率密度增大发生明显蓝移,具有Ⅱ类量子阱的特点. 应变补偿量子阱激光器在波长为1.3μm附近激射,阈值电流密度约为1.8kA/cm2.     

Cu溅射诱导增强量子阱混杂实验研究

在InP基异质结InGaAsP多量子阱(MQW)结构上溅射Cu/SiO2复合层,开展了量子阱混杂(QWI)材料的实验研究。经快速退火(RTA),实现了比常规无杂质空位扩散(IFVD)方法更大的带隙波长蓝移量。在750℃、200s的退火条件下,获得最大172nm的波长蓝移;通过改变退火条件,可实现不同程度的蓝移,满足光子集成技术中不同器件对带隙波长的需求。为了验证其用于光子集成领域的可行性,利用混杂技术分别制备了宽条激光器和单片集成电吸收调制激光器(EML)。在675℃退火温度,80s、120s和200s的退火时间下分别实现了61、81和98nm的波长蓝移;并且,相应的宽条激光器的电激射光(EL)谱偏调量与其材料的光致荧光(PL)谱偏调量基本一致。在675℃、120s退火条件下,制备的EML集成器件中,电吸收调制器(EAM)和分布反馈(DFB)激光器区的蓝移量分别83nm和23.7nm,相对带隙差为59.3nm。EML集成器件在激光器注入电流为100mA、调制器零偏压时出光功率达到9.6mW;EAM施加-5V反向偏压时静态消光比达16.4dB。     

不同Al组分的扩散阻挡层对无杂质空位诱导量子阱混杂的影响

为了获得更好的量子阱混杂效果,深入探讨了不同Al组分的扩散阻挡层对无杂质空位诱导量子阱混杂的影响。首先在两种不同Al组分外延片表面上分别生长了一层200 nm厚的SiO₂介质薄膜,然后在865～905℃温度范围内,进行了90 s的高温快速热退火处理。实验结果表明,低铝结构的波长蓝移量更大,且光致发光(Photoluminescence, PL)谱的强度下降更小,这说明在无杂质空位诱导量子阱混杂中,外延结构中的Al和Ga对点缺陷扩散的影响是不同的,Ga更有利于点缺陷的扩散。研究结果为无杂质空位诱导量子阱混杂的理论研究及器件的外延结构设计提供了参考。     

低能氦离子注入引入的量子阱混杂带隙波长蓝移

提出了采用低能氦离子注入多量子阱(MQW)材料和合适的快速退火条件,实现了MQW带隙波长的蓝移.用这种材料制作了FP腔激光器,与未注入器件相比,实现了37nm的激射波长蓝移.     

低能氦离子注入引入的量子阱混杂带隙波长蓝移

提出了采用低能氦离子注入多量子阱(MQW)材料和合适的快速退火条件,实现了MQW带隙波长的蓝移.用这种材料制作了FP腔激光器,与未注入器件相比,实现了37nm的激射波长蓝移.     

Cu/SiO2逐层沉积增强无杂质空位诱导InGaAsP/InGaAsP量子阱混杂

研究了Cu/SiO_2逐层沉积增强的无杂质空位诱导InGaAsP/InGaAsP多量子阱混杂(QWI)行为。在多量子阱(MQW)外延片表面,采用等离子体增强的化学气相沉积(PECVD)不同厚度的SiO_2,然后溅射5 nm Cu,在不同温度下进行快速热退火(RTA)诱发量子阱混杂。通过光荧光(PL)谱表征样品在QWI前后的变化。实验结果表明,当RTA温度小于700℃时,PL谱峰值波长只有微移,且变化与其他参数关系不大;当RTA温度大于700℃时,PL谱峰值波长移动与介质层厚度和RTA时间都密切相关,当SiO_2厚度为200 nm,退火温度为750℃,时间为200 s时,可获得54.3 nm的最大波长蓝移。该种QWI方法能够诱导InGaAsP MQW带隙移动,QWI效果与InGaAsP MQW中原子互扩散激活能、互扩散原子密度以及在RTA过程中热应力有关。     

Multi-bandgap photonic materials and devices fabricated by UV-laser induced quantum well intermixing

Ultraviolet(UV)-laser induced quantum well intermixing(QWI) technique can generate large multiple bandgap blue shifts in III-V quantum well semiconductor heterostructure.The application of the UV-laser QWI technique to fabricate multi-bandgap photonic devices based on compressively strained InGaAsP/InP quantum well laser microstructure is reported.We show that under certain UV-laser irradiation conditions,the photoluminescence(PL) intensity can be enhanced,and the full width at half maximum(FWHM) linewidth can be reduced.The blue shift of bandgap can reach as large as 145 nm,while the PL intensity is about 51% higher than that of the as-grown material.Experimental results of post growth wafer level processing for the fabrication of bandgap-shifted waveguides and laser diodes are presented.     

Impurity-free intermixing in compressively strained InGaAsP multiple quantum well structures

We report on controlled band gap modification in a compressively strained InGaAsP multi-quantum well-laser structure using different encapsulating layers followed by rapid thermal processing (RTP). The structure used was designed as a 1.55 μm laser with an active region consisting of three In_0.76Ga_0.24As_0.85P_0.15 quantum wells with In_0.76Ga_0.24As_0.52P_0.48 barriers grown by metal organic chemical vapor deposition. The heterostructure is capped with 100 nm thick InGaAs layer. Prior to RTP, the samples were coated with various dielectric layers or a thin film of low temperature (300°C) grown InP. Using a Si_xN_y film deposited by plasma-enhanced chemical vapor deposition with a refractive index of about 2.0, quantum well intermixing (QWI) was effectively suppressed. The suppression effect was independent of the Si_xN_y film thickness for layers of 30–2400 nm. With an e-beam-evaporated SiO₂ film, QWI was enhanced and a net blue shift of about 100 nm can be achieved between the samples covered with SiO₂ and Si_xN_y after RTP at 750°C for 100 s. Furthermore, InP grown at a low temperature by gas-source molecular beam epitaxy was proved to be even more efficient in enhancing QWI. Group V interstitial diffusion is used to explain the enhanced QWI between the wells and adjacent barriers which have the same group III compositions. Two-section tunable laser operated around 1.55 μm based on this laser structure was fabricated using this technique.     

Theoretical analysis of the inter-diffusion coefficients in the AlGaInP material quantum well intermixing

Quantum well intermixing (QWI) has been widely used in modifying the bandgap of semiconductor materials, post-growth; it has been investigated in fabricating non-absorbing mirror regions of laser cavities to improve output power. In this work, the QWI mechanism is briefly introduced. A concentration distribution function in multiple quantum wells is mathematically obtained for odd and even wells respectively. In addition, a 650 nm AlGaInP/GaInP quantum well wafer is fabricated by metal organic vapor phase epitaxy, and a series of quantum well intermixing experiments is accomplished by Zn impurity diffusions. Based on experimental data, a concentration distribution function is simulated and an inter-diffusion coefficient between Al and Ga is calculated. Finally, the effects of QWI on the inter-diffusion coefficient are discussed.     

光子吸收诱导无序技术的光荧光谱研究

运用 1 0 6 4μm连续输出的Nd∶YAG激光器 ,对与InP晶格匹配的InGaAsP四元系量子阱材料进行了光子吸收诱导无序 (PAID)技术的研究。通过光荧光谱 (PL)的测量 ,证明有量子阱混合现象产生。衬底预加热和聚焦激光束结果表明 ,PAID中辐照时间与衬底温度、辐照的平均功率密度密切相关。聚焦激光照射后的荧光双峰表明PAID有一定的定域处理能力。     

量子阱混杂单片集成宽可调谐激光器与半导体光放大器(英文)

采用量子阱方法集成半导体光放大器的取样光栅可调谐激光器,这在国内尚属首次．该器件波长调谐范围可达33nm,在放大器注入50mA电流时,输出光功率可达10mW,同时边模抑制比可达35dB以上．     

量子阱混杂单片集成宽可调谐激光器与半导体光放大器

采用量子阱方法集成半导体光放大器的取样光栅可调谐激光器,这在国内尚属首次.该器件波长调谐范围可达33nm,在放大器注入50mA电流时,输出光功率可达10mW,同时边模抑制比可达35dB以上.     

量子阱混杂单片集成宽可调谐激光器与半导体光放大器

采用量子阱方法集成半导体光放大器的取样光栅可调谐激光器,这在国内尚属首次.该器件波长调谐范围可达33nm,在放大器注入50mA电流时,输出光功率可达10mW,同时边模抑制比可达35dB以上.