High quality above 3-μm mid-infrared InGaAsSb/AlGaInAsSb multiple-quantum well grown by molecular beam epitaxy

The GaSb-based laser shows its superiority in the 3–4 μm wavelength range. However, for a quantum well(QW) laser structure of InGaAsSb/AlGaInAsSb multiple-quantum well(MQW) grown on GaSb, uniform content and high compressive strain in InGaAsSb/AlGaInAsSb are not easy to control. In this paper, the influences of the growth temperature and compressive strain on the photoluminescence(PL) property of a 3.0-μm InGaAsSb/AlGaInAsSb MQW sample are analyzed to optimize the growth parameters. Comparisons among the PL spectra of the samples indicate that the In0.485GaAs0.184Sb/Al0.3Ga0.45In0.25As0.22Sb0.78MQW with 1.72% compressive strain grown at 460 C posseses the optimum optical property. Moreover, the wavelength range of the MQW structure is extended to 3.83 μm by optimizing the parameters.     

High quality above 3-μm mid-infrared InGaAsSb/AIGaInAsSb multiple-quantum well grown by molecular beam epitaxy

The GaSb-based laser shows its superiority in the 3-4 ~tm wavelength range. However, for a quantum well （QW） laser structure of InGaAsSb/AIGaInAsSb multiple-quantum well （MQW） grown on GaSb, uniform content and high com- pressive strain in InGaAsSb/A1GaInAsSb are not easy to control. In this paper, the influences of the growth tempera- ture and compressive strain on the photoluminescence （PL） property of a 3.0μm lnGaAsSb/A1GaInAsSb MQW sample are analyzed to optimize the growth parameters. Comparisons among the PL spectra of the samples indicate that the Ino.485GaAso.184Sb/Alo.3Gao.45Ino.25Aso.22Sbo.78 MQW with 1.72% compressive strain grown at 460 ~C posseses the op- timum optical property. Moreover, the wavelength range of the MQW structure is extended to 3.83 μm by optimizing the parameters.     

GaAs-Based Metamorphic Long-Wavelength InAs Quantum Dots Grown by Molecular Beam Epitaxy

A bilayer stacked InAs/GaAs quantum dot structure grown by molecular beam epitaxy on an In0.05Ga0.95As metamorphic buffer is investigated. By introducing a InGaAs：Sb cover layer on the upper InAs quantum dots （QDs） layers, the emission wavelength of the QDs is extended successfully to 1.533 μm at room temperature, and the density of the QDs is in the range of 4× 10^9-8 ×10^9cm^-2. Strong photoluminescence （PL） intensity with a full width at half maximum of 28.6meV of the PL spectrum shows good optical quality of the bilayer QDs. The growth of bilayer QDs on metamorphic buffers offers a useful way to extend the wavelengths of GaAs-based materials for potential applications in optoeleetronic and quantum functional devices.     

Growth and Characterization of GaSb-Based Type-Ⅱ InAs/GaSb Superlattice Photodiodes for Mid-Infrared Detection

InAs/GaSb superlattiee （SL） midwave infrared photovoltaic detectors are grown by molecular beam epitaxy on GaSb（001） residud p-type substrates. A thick GaSb layer is grown under the optimized growth condition as a buffer layer. The detectors containing a 320-period 8ML/SML InAs/GaS5 SL active layer are fabricated with a series pixel area using anode sulfide passivation. Corresponding to 50% cutoff wavelengths of 5.0 μm at 77K, the peak directivity of the detectors is 1.6 × 10^10 cm.Hz^1/2 W^-1 at 77K.     

双层堆垛长波长InAs/GaAs量子点发光性质研究

研究了双层堆垛InAs/GaAs/InAs自组织量子点的生长和光致发光(PL)的物理性质。通过优化InAs淀积量、中间GaAs层厚度以及InAs量子点生长温度等生长条件,获得了室温光致发光1391～1438nm的高质量InAs量子点。研究发现对量子点GaAs间隔层实施原位退火、采用Sb辅助生长InGaAs盖层等方法可以增强高密度(2×1010 cm-2)InAs量子点的发光强度,减小光谱线宽,改善均匀性和红移发光波长。     

Influence of Growth Parameters of Frequency-Radio Plasma Nitrogen Source on Extending Emission Wavelengths from 1.31 μm to 1.55 μm GaInNAs/GaAs Quantum Wells Grown by Molecular-Beam Epitaxy

High （42.5%） indium content GaInNAs/GaAs quantum wells with room temperature emission wavelength from 1.3μm to 1.5μm range were successfully grown by Radio Frequency Plasma Nitrogen source assisted Molecular Beam Epitaxy, The growth parameters of plasma power and N2 flow rate were optimized systematically to improve the material quality. Photoluminescence and transmission electron microscopy measurements showed that the optical and crystal quality of the 1.54μm GaInNAs/GaAs QWs was kept as comparable as that in 1.31 μm.     

嵌埋在SiO2基质中的nc-Ge的制备及其发光现象

采用等离子体化学汽相淀积技术生长a-Ge_xSi_1-x∶H薄膜，然后在800℃，10⁵Pa下于传统开口管式炉中氧化热处理，制备嵌埋在SiO₂中的nc-Ge微晶粒．利用傅里叶变换红外光谱、喇曼光谱和X射线衍射谱分析样品的微结构，研究a-Ge_xSi_1-x∶H薄膜的氧化过程中发生的化学和物理变化，并用平衡态化学反应热理论加以解释．在某些样品中观察到室温下的光致发光现象，采用Brus电 关键词：     

Evolution of surface morphology and photoluminescence characteristics of 1.3-μm In_(0.5)Ga_(0.5)As/GaAs quantum dots grown by molecular beam epitaxy

Evolution of surface morphology and optical characteristics of 1.3-μm In0.5Ga0.5As/GaAs quantum dots （QDs） grown by molecular beam epitaxy （MBE） are investigated by atomic force microscopy （AFM） and photoluminescence （PL）. After deposition of 16 monolayers （ML） of In0.5Ga0.5As, QDs are formed and elongated along the [120] direction when using sub-ML depositions, while large size InGaAs QDs with better uniformity are formed when using ML or super-ML depositions. It is also found that the larger size QDs show enhanced PL efficiency without optical nonlinearity, which is in contrast to the elongated QDs.     

原子氢辅助分子束外延GaAs(331)A表面形貌演化

研究了GaAs高指数面(331)A在原子氢辅助下分子束外延形貌的演化.原子力显微镜测试表明：在常规分子束外延情况下,GaAs外延层台阶的厚度和台面的宽度随衬底温度的升高而增加,增加外延层厚度会导致台阶的密度和台面的宽度增加然后饱和.而在原子氢辅助分子束外延情况下,当GaAs淀积量相同时GaAs外延层台阶的密度增大宽度减小.认为这是由于原子氢的作用导致Ga原子迁移长度的减小.在GaAs(331)A台阶基底上生长出InAs自组织纳米线,用光荧光测试研究了其光学各项异性特征.