全固源分子束外延InAsP/InGaAsP多量子阱1.55μm激光器

利用新型全固源分子束外延技术 ,对 1 .5 5 μm波段的 In As P/ In Ga As P应变多量子阱结构的生长进行了研究。实验表明 ,较低的生长温度或较大的 / 束流比有利于提高应变多量子阱材料的结构质量 ,而生长温度对材料的光学特性有较大的影响。在此基础上生长了分别限制多量子阱激光器结构 ,制作的氧化物条形宽接触激光器实现了室温脉冲工作 ,激射波长为 1 5 63 nm,阈值电流密度为 1 .4k A/ cm2 。这是国际上首次基于全固源分子束外延的 1 .5 5 μm波段 In As P/ In Ga As P多量子阱激光器的报道     

掺In对反型AlGaAs/GaAs异质界面质量的改善及其应用

研究了Al Ga As层掺1%的In对Al Ga As/Ga As量子阱光致发光谱的半峰宽的影响.2 5 K的光致发光结果表明,In作为表面活化剂能有效改善Al Ga As/Ga As异质界面的粗糙度.将此方法应用到反型Al Ga As/Ga As高电子迁移率晶体管(HEMT)材料结构中,Hall测量表明该方法能有效提高反型HEMT的电学性能     

离子损伤对等离子体辅助分子束外延生长的 Ga NAs/ Ga As和Ga In NAs/ Ga As量子阱的影响

研究了离子损伤对等离子体辅助分子束外延生长的 Ga NAs/ Ga As和 Ga In NAs/ Ga As量子阱的影响 .研究表明离子损伤是影响 Ga NAs和 Ga In NAs量子阱质量的关键因素 .去离子磁场能有效地去除了等离子体活化产生的氮离子 .对于使用去离子磁场生长的 Ga NAs和 Ga In NAs量子阱样品 ,X射线衍射测量和 PL 谱测量都表明样品的质量被显著地提高 .Ga In As量子阱的 PL 强度已经提高到可以和同样条件下生长的 Ga In As量子阱相比较 .研究也表明使用的磁场强度越强 ,样品的光学质量提高越明显     

InGaAs/InP量子线的子带结构和光学增益

采用有效质量理论 6带模型 ,计算了 In0 .53Ga0 .4 7As/ In P量子线的光学性质 ,具体计算了In0 .53Ga0 .4 7As/ In P量子线的能带结构、态密度、载流子浓度、光学跃迁矩阵元和光学增益谱 ,并把量子线的光学增益谱和量子阱的光学增益谱作了比较。     

磁场对氮化物抛物量子阱中束缚极化子的影响

采用改进的Lee-Low-Pines中间耦合方法研究了在外磁场作用下纤锌矿氮化物抛物量子阱中极化子能级,给出不同磁场下极化子基态能量、结合能随阱宽L的变化关系以及能量随磁场强度B变化的函数关系。在计算抛物量子阱材料中考虑了纤锌矿GaN和Al0.3Ga0.7N构成的抛物量子阱中材料中准LO和准TO声子模的各向异性以及外磁场对极化子能量的影响。结果表明:纤锌矿氮化物抛物量子阱材料中电子-声子相互作用和外磁场对极化子能级有明显的影响。极化子基态能量、结合能随阱宽的增加而减小,随磁场的增加而增大,电子-声子相互作用使极化子能量降低,并且GaN/Al0.3Ga0.7N抛物量子阱对极化子的束缚程度比GaAs/Al0.3Ga0.7As抛物量子阱强,因此,在GaN/Al0.3Ga0.7N抛物量子阱中束缚于杂质中心处的电子比在GaAs/Al0.3Ga0.7As抛物量子阱中束缚于杂质中心处的电子稳定。     

压应变In_(0.63)Ga_(0.37)As/InP单量子阱的变温光致发光研究

我们对用GSMBE技术生长的In0.63Ga0.37AS／lnP压应变单量子阱样品进行了变温光致发光研究，In0.63Ga0.37As阱宽为1nm到11nm，温度变化范围为10K到300K．发现不同阱宽的压应变量子阱中激子跃迁能量随温度的变化关系与体In0.53Ga0.47As材料相似，温度系数与阱宽无关．对1nm的阱，我们观察到其光致发光谱峰为双峰，经分析表明，双峰结构由量子阱界面起伏一个分子单层所致．说明量子阱界面极为平整，样品具有较高的质量．考虑到组分效应、量子尺寸效应及应变效应，计算了In0.63G0.37As／InP压应变量子阱中的激子跃迁能量，理论计算结果与实验结果符合得很好     

1.55μm张应变InGaAsP/InGaAsP量子阱偏振不灵敏半导体光放大器的优化设计

优化设计了 1.5 5 μm In Ga As P/In Ga As P张应变量子阱偏振不灵敏半导体光放大器的结构 .利用 k· p方法计算了多量子阱的价带结构 ,计算中考虑了 6× 6有效质量哈密顿量 .从阱宽、应变、注入载流子密度等方面计算了量子阱模式增益的偏振相关性 .     

低压金属有机化合物气相外延生长的 (Al_x Ga_(1-x))_(0 .5 1)In_(0 .49)P折射率测量(英文)

采用测量反射谱方法确定了低压金属有机化合物气相外延生长的与 Ga As衬底匹配 (Alx Ga1 - x) 0 .5 1 In0 .49P外延材料的折射率 .实验中测量的反射谱波长范围为 0 .5— 2 .5 μm.在拟合实验数据过程中采用了单振子模型 .折射率数据用于分析应变量子阱 Ga In P/ Al Ga In P可见光激光二极管波导 ,计算出的器件远场图与实验数据吻合很好 .     

808nm InGaAlAs垂直腔面发射激光器的结构设计

为实现垂直腔面发射半导体激光器(VCSEL)在808 nm波长的激射,对VCSEL芯片的整体结构进行了设计。基于应变量子阱的能带理论、固体模型理论、克龙尼克-潘纳模型和光学传输矩阵方法,计算了压应变InGaAlAs量子阱的带隙、带阶、量子化子能级以及分布布拉格反射镜(DBR)的反射谱,从而确定了量子阱的组分、厚度以及反射镜的对数。数值模拟的结果表明,阱宽为6 nm的In0.14Ga0.74Al0.12As/Al0.3Ga0.7As量子阱,在室温下激射波长在800 nm左右,其峰值材料增益在工作温度下达到4000 cm-1;渐变层为20 nm的Al0.9Ga0.1As/Al0.2Ga0.8As DBR,出光p面为23对时反射率为99.57%,全反射n面为39.5对时反射率为99.94%。设计的顶发射VCSEL结构通过光电集成专业软件(PICS3D)验证,得到室温下的光谱中心波长在800 nm处,证实了结构设计的正确性。     

低压金属有机化合物气相外延生长的 (Al_x Ga_(1-x))_(0.51)In_(0.49)P折射率测量

采用测量反射谱方法确定了低压金属有机化合物气相外延生长的与 Ga As衬底匹配 (Alx Ga1 - x) 0 .5 1 In0 .49P外延材料的折射率 .实验中测量的反射谱波长范围为 0 .5— 2 .5 μm.在拟合实验数据过程中采用了单振子模型 .折射率数据用于分析应变量子阱 Ga In P/ Al Ga In P可见光激光二极管波导 ,计算出的器件远场图与实验数据吻合很好 .     

LP－MOCVD生长InGaAs／GaAs量子阱

用低压ＭＯＣＶＤ（ＬＰ－ＭＯＣＶＤ）生长三种不同的ＩｎＧａＡｓ／ＧａＡｓ应变层量子阱材料，其中两种含ＡｌＧａＡｓ限制层。结果表明，ＡｌＧａＡｓ限制层对量子阱的发光强度影响很大，与没有ＡｌＧａＡｓ限制层的结果相比，带ＡｌＧａＡｓ限制层的结构的发光强度要强一个数量级以上。在低温（１８Ｋ）ＰＬ光谱图中，我们看到，除了存在主峰以外，在主峰两侧还各有一个子峰，这些子峰可能与量子阱的质量有关。     

Super-flat (411)A interfaces and uniformly corrugated (775)B interfaces in GaAs/AlGaAs and InGaAs/InAlAs heterostructures grown by molecular beam epitaxy

Extremely flat interfaces, i.e. effectively atomically flat interfaces over a wafer-size area were realized in GaAs/AlGaAs quantum wells (QWs) grown on (411)A GaAs substrates by molecular beam epitaxy (MBE). These flat interfaces are called as “(411)A super-flat interfaces”. Besides in GaAs/AlGaAs QWs, the (411)A super-flat interfaces were formed in pseudomorphic InGaAs/AlGaAs QWs on GaAs substrates and in pseudomorphic and lattice-matched InGaAs/InAlAs QWs on InP substrates. GaAs/AlGaAs resonant tunneling diodes and InGaAs/InAlAs HEMT structures with the (411)A super-flat interfaces were confirmed to exhibit improved characteristics, indicating high potential of applications of the (411)A super-flat interfaces. High density, high uniformity and good optical quality were achieved in (775)B GaAs/(GaAs)_m(AlAs)_n quantum wires (QWRs) self-organized in a GaAs/(GaAs)_m(AlAs)_n QW grown on (775)B GaAs substrates by MBE. The QWRs were successfully applied to QWR lasers, which oscillated at room temperature for the first time as QWR lasers with a self-organized QWR structure in its active region. These results suggest that MBE growth on high index crystal plane such as (411)A or (775)B is very promising for developing novel semiconductor materials for future electron devices.     

Monte Carlo simulation of electron transport efficiency of an InGaAs/InP hot-electron transistor

Electron transport efficiency of an InGaAs/InP hot-electron transistor (HET) is determined by a Monte Carlo method including alloy scattering in an InGaAs base. Results are compared with those of a GaAs/AlGaAs HET. It is found that the InGaAs/InP HET offers a higher current gain than that of a GaAs/AlGaAs HET by an order of magnitude.     

Metalorganic vapor phase epitaxy growth and properties of GaAs/AlGaAs and InGaAs/GaAs quantum well structures on (111)A GaAs substrates

We review the recent advances in the fabrication and properties of GaAs/AlGaAs and InGaAs/GaAs quantum well (QW) structures grown on (111)A GaAs substrates by atmospheric pressure metalorganic vapor phase epitaxy (MOVPE). We show that a 25-period GaAs/AlGaAs multi-QW (MQW) structure was fabricated with good crystal quality, high photoluminescence (PL) emission intensity and monolayer (ML) interfacial roughness. A PL full width at half maximum (FWHM) of 10.5 meV was achieved for a 25-period MQW with a well width of 44 Å. This is the narrowest linewidth reported to date for any similar structures grown on (111)A or B substrates by any growth technique. We also report the properties of an InGaAs/GaAs single quantum well structure grown on (111)A GaAs. For this structure, the PL FWHM value was 9.1 meV, corresponding to a 1 ML interfacial roughness for a well width of 41 Å. This is the first demonstration of an InGaAs/GaAs quantum well structure grown on (111)A or (111)B GaAs by MOVPE.     

Electron nonelastic scattering by confined and interface polar optical phonons in a modulation-doped AlGaAs/GaAs/AlGaAs quantum well

The calculations of electron scattering rates by polar optical (PO) phonons in an AlGaAs/GaAs/AlGaAs quantum well (QW) with a different width and doping level are performed. The electron-and PO-phonon scattering mechanisms which are responsible for the alternate dependence of electron mobility on a QW width, as well as for the decrease of conductivity in the QW with increasing sheet electron concentration, are determined. It is shown that the enhancement of the scattering rate by PO-phonon absorption when the lower subband electron gas is degenerated is responsible for the decrease of QW conductivity with increasing sheet electron concentration. The competition between the decrease of the intrasubband scattering and the increase of the intersubband scattering by PO-phonon absorption is responsible for the alternate changes of the mobility with a QW width.     

Fabrication of dry-etched mirrors in GaAs-based and InP-based lasers using chemically assisted ion-beam etching at low temperatures

We have fabricated dry-etched mirrors in high-speed InGaAs/GaAs/AlGaAs pseudomorphic multiple quantum well ridge-waveguide lasers at 60°C and in InGaAs/InP bulk lasers at 5°C using enhanced chemically assisted ion-beam etching (CAIBE) technique. The technique allows the etching of laser structures with good surface morphology and excellent anisotropy without cold traps in the etching system. Characteristics of the dry-etched facet lasers match those of cleaved devices. The low sample temperatures for etching allowed the use of standard photoresists as etch masks.     

Optical anisotropy of InGaAs quantum dots

Polarization studies of InGaAs/GaAs quantum dots (QDs) synthesized in the submonolayer deposition mode (SMLQDs) on a singular GaAs (100) surface are carried out using photoluminescence spectroscopy. The influence of the effective In content in InGaAs SMLQDs and the effect of a wide-gap AlGaAs matrix on the optical anisotropy of the QDs are investigated. The highest degree (>15%) of optical anisotropy between the [011] and [0 $ \bar 1 $ 1] directions in the emission corresponding to the ground state of InGaAs/GaAs SMLQDs is observed for an effective In content of ～40%. The use of a wide-gap AlGaAs matrix resulted in an increase in the optical anisotropy of InGaAs SMLQDs by a factor of 1.5. It is found that vertical stacking of In(Ga)As/AlGaAs SMLQDs in the vertical-coupling mode (with spacer-layer thicknesses of 5–10 nm) leads to a further increase in the degree of optical anisotropy, which becomes as high as 25% on average. According to the data of transmission electron microscopy, the optical anisotropy of the ground-state photo-luminescence is predominantly caused by the anisotropy of the lateral dimensions of QDs in the [011] and [0 $ \bar 1 $ 1] directions.     

Optimal quantum well width and the effect of quantum well position on the performance of transistor lasers

Transistor laser (TL) model based on InGaP/GaAs/InGaAs/GaAs is analyzed and presented. It is realized that quantum well (QW) with width of 10 nm may be formed for low base threshold current density J th . The emission wavelength is found to be 1.05 μm, and the indium (In) composition is 0.25 for optimal QW width. It is identified that J th decreases with the movement of QW towards the base-emitter (B-E) interface. Small signal optical response is calculated, and the effect of QW position is studied. The bandwidth is enhanced due to the movement of the QW towards the emitter base junction.     

LP－MOCVD生长伸张应变InGaAs／InP多量子阱的研究

首先从理论上研究了在应变情况下量子阱中能级的计算，然后利用ＬＰ－ＭＯＣＶＤ研究了ＩｎＧａＡｓ／ＩｎＰ组份的控制及生长条件，最后生长伸张应变为０．５％的四个量子阱ＩｎＧａＡｓ／ＩｎＰ结构材料，利用ＰＬ光谱测量得最小阶宽为１．８ｎｍ。     

LP－MOCVD生长伸张应变InGaAs／InP多量子阱的研究

首先从理论上研究了在应变情况下量子阱中能级的计算，然后利用ＬＰ－ＭＯＣＶＤ研究了ＩｎＧａＡｓ／ＩｎＰ组份的控制及生长条件，最后生长伸张应变为０．５％的四个量子阱ＩｎＧａＡｓ／ＩｎＰ结构材料，利用ＰＬ光谱测量得最小阶宽为１．８ｎｍ。