微腔调制常温Ge量子点光致发光特性

报道了微腔对Ge量子点常温光致发光的调制特性.生长在SOI硅片上的Ge量子点的常温光致发光呈多峰分布,随波长增加,峰与峰之间的间隔增加.这种多峰结构与SOI硅片所形成的微腔有关,只有满足特定波长的光致发光才能透出腔体并被探测器搜集.模拟结果与实验结果吻合得很好,变功率实验也进一步证实了该结论.     

微腔调制常温Ge量子点光致发光特性

报道了微腔对Ge量子点常温光致发光的调制特性.生长在SOI硅片上的Ge量子点的常温光致发光呈多峰分布,随波长增加,峰与峰之间的间隔增加.这种多峰结构与SOI硅片所形成的微腔有关,只有满足特定波长的光致发光才能透出腔体并被探测器搜集.模拟结果与实验结果吻合得很好,变功率实验也进一步证实了该结论.     

微腔调制常温Ge量子点光致发光特性

报道了微腔对Ge量子点常温光致发光的调制特性. 生长在SOI硅片上的Ge量子点的常温光致发光呈多峰分布，随波长增加，峰与峰之间的间隔增加. 这种多峰结构与SOI硅片所形成的微腔有关，只有满足特定波长的光致发光才能透出腔体并被探测器搜集. 模拟结果与实验结果吻合得很好，变功率实验也进一步证实了该结论.     

反向偏压调制下Ⅰ型阱结构体系光致发光特性的研究

实验过程中研究了8-hydroxyq-uinoline aluminum(Alq3)和2-(4-biphenylyl)-5(4-tert-butyl-phenyl)-1,3,4-oxadiazole(PBD)构成的Ⅰ型有机阱结构器件在反向偏压调制下的光致发光.器件的光致发光光谱主要是Alq3的发光,不同周期数的阱结构器件在反向电场作用下,光致发光的猝灭程度不同.     

InP衬底上晶格匹配四元系InAlGaAs的气态源分子束外延生长

采用高分辨率X射线衍射摇摆曲线、光致发光以及霍尔测试对采用气态源分子束外延方法生长的四元系In-AlGaAs材料性质进行了表征。摇摆曲线结果表明,根据计算数据所生长的InAlGaAs样品与InP衬底基本匹配.光致发光和霍尔测试结果显示随着Al组分的增加,样品的光致发光强度、电子浓度和迁移率均有所下降.样品的三族元素组分由光致发光及X射线衍射实验获得,测试结果与设计值吻合,Al组分的实验设计值与测试结果的关系提供了一种实用的精确控制组分的方法.     

退火对a-Si_xC_(1-x):H薄膜光学性质的影响

研究了退火对α-Si_xC_(1-x):H薄膜红外吸收和光致发光性质的影响.实验结果表明:低温退火使与氢有关的红外吸收和积分发光强度增加;而高温退火使与氢有关的红外吸收和积分发光强度减弱;同时,随着退火温度升高,光致发光光谱的峰值能量位置移向低能.文中对退火引起红外吸收和光致发光性质的变化机理进行了讨论。     

Ⅲ-Ⅴ族半导体材料的低温光致发光

<正> 砷化镓、磷化铟等Ⅲ-Ⅴ族化合物半导体已广泛应用于微波、光电等器件中.为了提高材料质量,我们建立了灵敏、非破坏性的检测手段——低温光致发光.它还适合于微区和薄膜的研究,是分析GaAs等Ⅲ-Ⅴ族半导体材料中杂质和缺陷的有效方法之一.本文将介绍低温光致发光的实验技术和部份实验结果.     

自组装制备硅纳米线阵列及其光致发光特性研究

用微电化学催化腐蚀法制备了硅纳米线阵列,通过扫描电镜(SEM)观察了样品的表面形貌.用荧光光谱仪测量了有序硅纳米线阵列的光致发光特性,发现当激发波长增加时,有序硅纳米线阵列的光致发光峰位单调红移,发光强度也单调增强.对比多孔硅的发光机理和现有实验条件,对有序硅纳米线阵列可能的发光机理进行了讨论.     

有机小分子掺杂的聚合物发光二极管电致发光及其发射机制

在新型空穴传输聚合物聚TPD(PTPD)中掺杂电子传输有机小分子荧光染料Rubrene制成薄膜器件.考察了影响聚合物掺杂小分子薄膜器件发光性能的因素.实验表明,通过在器件中掺杂,可以控制器件所发光的颜色.研究了PTPD掺杂Rubrene分子薄膜的电致发光光谱和光致发光光谱.由实验可知.在光致发光中存在从PTPD向Rubrene的能量传递和电荷转移,而电致发光则存在从PTPD向Rubrene的能量传递和Rubrene分子对载流子的俘获.即掺杂器件的发射机制为载流子陷阱和Forster能量转换过程的共同作用.     

有机小分子掺杂的聚合物发光二极管电致发光及其发射机制

在新型空穴传输聚合物聚TPD(PTPD)中掺杂电子传输有机小分子荧光染料Rubrene制成薄膜器件.考察了影响聚合物掺杂小分子薄膜器件发光性能的因素.实验表明,通过在器件中掺杂,可以控制器件所发光的颜色.研究了PTPD掺杂Rubrene分子薄膜的电致发光光谱和光致发光光谱.由实验可知.在光致发光中存在从PTPD向Rubrene的能量传递和电荷转移,而电致发光则存在从PTPD向Rubrene的能量传递和Rubrene分子对载流子的俘获.即掺杂器件的发射机制为载流子陷阱和Forster能量转换过程的共同作用.     

InGaAs-GaAs应变量子阱的光学性质

本文详细研究了In_xGa_(1-x)As/GaAs应变量子阱的光学性质.用一维方势阱模型和应变对能带结构的影响解释了荧光发射峰.观察到应变对热电子弛豫过程的影响,并发现用光荧光实验确定的临界厚度基本满足力学平衡模型.     

GaN薄膜发光特性的研究

通过扫描电子显微镜和室温光荧光谱仪研究了生长气氛、缓冲层厚度、掺杂浓度不同对GaN薄膜发光特性的影响。实验证明,缓冲层可以较好地改善外延膜的结构和表面形貌。n型GaN薄膜的光荧光谱图显示,主峰的积分强度随着掺硅浓度的增高而增高,黄带峰的发光强度反而下降。     

Optical properties of strained layer (111)B Al0.15Ga0.85As-In0.04Ga0.96as quantum well heterostructures

Data presented here demonstrate that strained-layer (111)B Al_0.15Ga_0.85As-In_0.04Ga_0.96As quantum wells exhibit unique optical properties when compared to otherwise identical (100) oriented strained layers. Photoluminescence measurements identify a strain-induced electric field of order 6.7 Vμm^-1 within the (111)B quantum well that is not present for the (100) case. Photoluminescence excitation spectroscopy measurements show that the heavy-hole to light-hole energy band splitting is approximately 7 meV larger for the (111)B structure than for the (100) structure. Howard Hughes Doctoral Fellow IBM Graduate Fellow     

The excition tunneling in ZnCdSe/ZnSe asymmetric double quantum well

Photoluminescence spectra of asymmetric double-quantum-well structure are studied in this paper. We show the excitation power dependence of exciton tunneling. Due to the different tunneling time of electrons and holes, space-charge effect is observed.     

Photoluminescence characteristics of InP annealed in phosphorus and iron phosphide ambiences

Photoluminescence (PL) spectroscopy has been used to study InP annealed in phosphorus and iron phosphide ambiences. Noticeable PL emissions related with thermally induced defects have been detected in undoped InP annealed in iron phosphide ambience. Origins of the PL emissions have been discussed.     

Effect of CdSe/ZnS quantum dots on color purity and electrical properties of polyfluorene based hybrid light emitting diode

We report enhanced color purity of hybrid organic-inorganic light emitting diode based on polyfluorene-CdSe/ZnS quanum dot (QD) blend as emissive layer. Effect on structural, optical and electrical properties of different doping concentration (0–100 wt.%) of QD in polyfluorene (PFO) was studied. Photoluminescence and electroluminescence spectra confirm the β-formation of PFO by incorporation of CdSe/ZnS QD. Photoluminescence (PL) of blend film was also compared with another method based on one dimensional photonic band gap (1D-PBG) structure that has been used for color purity. In both the cases, that is, QD doped device and 1D-PBG based structures the narrowing of PL spectra was observed. But the fabrication of QD-doped device for color purity is easier than fabricating 1D-PBG structure using multilayer dielectric coating. The present study might find application for QD based color displays, where color purity is an important requirement.     

Disordering of Ga0.47In0.53As/InP multiplequantum well layers by sulphur diffusion

The disordering of Ga_0.47In_0.53As/InP MQW layers by the diffusion of sulphur is reported for the first time. Photoluminescence measurements indicate that this results in a larger bandgap material. SIMS profiles show that intermixing of both group III and V elements occurs between wells and barriers     

Triangular and hexagonal high Q-factor 2-D photonic bandgapcavities on III-V suspended membranes

We demonstrate InP-based triangular and hexagonal two-dimensional (2-D) planar photonic bandgap (PGB) crystal-based microcavities, positioned on a suspended membrane. Photoluminescence spectra of the structure clearly show well-resolved cavity modes, whose structure depends on the cavity shape. Q factors from 200 up to at least 900 are derived     

Polymer Multilayer Microspheres Loaded with Semiconductor Quantum Dots

Optically active nanostructures comprised of polymer multilayer microspheres surrounding semiconductor quantum dots are studied. Comparative analysis of the optical properties of the microspheres with four alternating layers with different refractive indices is performed. Photoluminescence and extinction characteristics of the microspheres are determined by the dimensions, internal structure, and the average refractive index of the particles.     

~1.40 eV emission band in GaAs

Photoluminescence techniques have been used to detect and characterise the ~ 1.40 eV emission band in an Mn-doped GaAs MBE epilayer and heated semi-insulating Cr-doped GaAs. An activation energy ~ 110 ± 5 meV is obtained from the temperature quenching of the emission intensity, and evidence indicated that physical movement of the Mn atom is responsible for type conversion.