1.5μmInGaAsP/InP P型衬底隐埋新月型（PBC）结构激光器

于2010-11-23批量导入

Iron related emission spectra in InP

This paper presents a detailed PL study of Fe2+ related four zero-phonon(ZP) lines and their related phonon sidebands. Four zero-phonon transitions at approximate to 2800 cm(-1) along with the accompanying phonon sidebands extending down to 2400 cm(-1). There are ta two prominent regions in the phonon sidebands. One is ascribed to coupling to acoustic-type phonons (2700 cm(-1) region), the other is due to coupling to optic-type phonons (2500 cm(-1) region). Beside broad coupling with lattice modes, there are several groups of lines. They are ascribed to resonant modes, impurities induced gap modes and local modes.

Twin and grain boundary in InP: A synchrotron radiation study

Experimentally observed X-ray reflectivity curves show bi-crystal(twin) characteristics. The study revealed that there was defect segregation at the twin boundary. Stress was relaxed at the edge of the boundary. Relaxation of the stress resulted in formation of twin and other defects. As a result of formation of such defects, a defect-free and stress-free zone or low defect density and small stress zone is created around the defects. So a twin model was proposed to explain the experimental results. Stress(mainly thermal stress), chemical stoichiometry deviation and impurities nonhomogeneous distributions are the key factors that cause twins in LEC InP crystal growth. Twins on (111) face in LEC InP crystal were studied. Experimental evidence of above mentioned twin model and suggestions on how to get twin-free LEC InP single crystals will be discussed.

Hydrogen related defects in InP

Local vibrational modes(LVMs) in tenths of InP samples reveal clearly existence of complexes related to hydrogen. Complexes of vacancy at indium site with one to four hydrogen atom(s) and isolated hydrogen or hydrogen dimers and complexes of hydrogen with various impurities and intrinsic defects are investigated by FTIR. Especially hydrogen related complexes between various transition metals and hydrogen or hydrogen related complexes between hydrogen with point defects. New LVMs related to hydrogen will be reported in this paper. Dynamical formation mechanism of defects in the annealed nominally undoped semiinsulating InP obtained by high pressure, high temperature annealing of ultra purity materials is proposed. Hydrogen can acts as actuator for antistructure defects production. Structural, electronic and vibrational properties of LVMs related to hydrogen as well as their temperature effects are discussed.

High performance 1.55 mu m InGaAsP/InP strained layer quantum well laser diodes fabricated by MOCVD overgrowth method

High performance uncooled 1.55 mu m InGaAsP/InP strained layer quantum well (SL-QW) lasers grown by low pressure metal organic chemical vapor deposition (LP-MOCVD) were reported in this paper. Whole MOCVD over growth method were applied in this work. The threshold currents of 5mA and the highest lasing temperature of 122 degrees C were obtained.

1.3 mu m InGaAsP/InP strained layer multi-quantum-well complex-coupled distributed feedback laser

1.3 mu m strained-layer multi-quantum wells complex-coupled distributed feedback lasers with a wide temperature range of 20 to 100 degrees C are reported. The low threshold current of 10mA and high single-facet slope efficiency of 0.3mW/mA were obtained for an as cleaved device. The single mode yield was as high as 80%.

Symmetry in the diagonal self-assembled InAs quantum wire arrays on InP substrate

Diagonal self-assembled InAs quantum wire (QWR) arrays with the stacked InAs/In0.52Al0.48As structure are grown on InP substrates, which are (001)-oriented and misoriented by 6degrees towards the [100] direction. Both the molecular beam epitaxy (MBE) and migration enhanced epitaxy (MEE) techniques are employed. Transmission electron microscopy reveals that whether a diagonal InAs QWR array of the stacked InAs/InAlAs is symmetrical about the growth direction or not depends on the growth method as well as substrate orientation. Asymmetry in the diagonal MEE-grown InAs QWR array can be ascribed to the influence of surface reconstruction on upward migration of adatoms during the self-assembly of the InAs quantum wires.

Optical properties of self-assembled ternary In(GA/Al)As quantum dots on (100) and (N 1 1)B InP substrates

In this paper, we investigated the self-assembled quantum dots formed on (100) and (N11)B (N = 2, 3, 4, 5) InP substrates by molecular beam epitaxy (MBE). Two kinds of ternary QDs (In0.9Ga0.1As and In0.9Al0.1As QDs) are grown on the above substrates; Transmission electron microscopy (TEM) and photoluminescence (PL) results confirm QDs formation for all samples. The PL spectra reveal obvious differences in integral luminescence, peak position, full-width at half-maximum and peak shape between different oriented surfaces. Highest PL integral intensity is observed from QDs on (411)B surfaces, which shows a potential for improving the optical properties of QDs by using high-index surface. (C) 2000 Elsevier Science B.V. All rights reserved.

InP-based optoelectronic devices for optical fiber communications

In this contribution we report the research and development of 1.55 mu m InGaAsP/InP gain-coupled DFB laser with an improved injection-carrier induced grating and of high performance 1.3 mu m and 1.55 mu m InGaAsP/InP FP and DFB lasers for communications. Long wavelength strained MQW laser diodes with a very low threshold current (7-10 mA) have been fabricated. Low pressure MOVPE technology has been employed for the preparation of the layered structure. A novel gain-coupled DFB laser structure with an improved injection-carrier modulated grating has been proposed and fabricated. The laser structures have been prepared by hybrid growth of MOVPE and LPE techniques and reasonably good characteristics have been achieved for resultant lasers. High performance 1.3 mu m and 1.55 mu m InGaAsP/InP DFB lasers have successfully been developed for CATV and trunk line optical fiber communication.

High Characteristic Temperature InGaAsP/InP Tunnel Injection Multiple-Quantum-Well Lasers

We fabricate 1.5 mu m InGaAsP/InP tunnel injection multiple-quantum-well (TI-MQW) Fabry-Perot (F-P) ridge lasers. The laser heterostructures, including an inner cladding layer and an InP tunnel barrier layer, are grown by metal-organic chemical-vapor deposition (MOCVD). Characteristic temperature.. 0 of 160K at 20 degrees C is obtained for 500-mu m-long lasers. T-0 is measured as high as 88K in the temperature range of 15-75 degrees C. Cavity length dependence of T-0 is investigated.

Directional Emission InGaAsP/InP Mirocylinder Lasers

IEEE

Integral energy performance characterization of semi-transparent photovoltaic elements for building integration under real operation conditions

In this paper, a methodology for the integral energy performance characterization (thermal, daylighting and electrical behavior) of semi-transparent photovoltaic modules (STPV) under real operation conditions is presented. An outdoor testing facility to analyze simultaneously thermal, luminous and electrical performance of the devices has been designed, constructed and validated. The system, composed of three independent measurement subsystems, has been operated in Madrid with four prototypes of a-Si STPV modules, each one corresponding to a specific degree of transparency. The extensive experimental campaign, continued for a whole year rotating the modules under test, has validated the reliability of the testing facility under varying environmental conditions. The thermal analyses show that both the solar protection and insulating properties of the laminated prototypes are lower than those achieved by a reference glazing whose characteristics are in accordance with the Spanish Technical Building Code. Daylighting analysis shows that STPV elements have an important lighting energy saving potential that could be exploited through their integration with strategies focused to reduce illuminance values in sunny conditions. Finally, the electrical tests show that the degree of transparency is not the most determining factor that affects the conversion efficiency.

Experiências do desenvolvimento de transformador para alta temperatura baseado em isolação semi-híbrida e óleo vegetal isolante.

O transformador de potência é um importante equipamento utilizado no sistema elétrico de potência, responsável por transmitir energia elétrica ou potência elétrica de um circuito a outro e transformar tensões e correntes de um circuito elétrico. O transformador de potência tem ampla aplicação, podendo ser utilizado em subestações de usinas de geração, transmissão e distribuição. Neste sentido, mudanças recentes ocorridas no sistema elétrico brasileiro, causadas principalmente pelo aumento considerável de carga e pelo desenvolvimento tecnológico tem proporcionado a fabricação de um transformador com a aplicação de alta tecnologia, aumentando a confiabilidade deste equipamento e, em paralelo, a redução do seu custo global. Tradicionalmente, os transformadores são fabricados com um sistema de isolação que associa isolantes sólidos e celulose, ambos, imersos em óleo mineral isolante, constituição esta que define um limite à temperatura operacional contínua. No entanto, ao se substituir este sistema de isolação formado por papel celulose e óleo mineral isolante por um sistema de isolação semi- híbrida - aplicação de papel NOMEX e óleo vegetal isolante, a capacidade de carga do transformador pode ser aumentada por suportar maiores temperaturas. Desta forma, o envelhecimento do sistema de isolação poderá ser em longo prazo, significativamente reduzido. Esta técnica de aumentar os limites térmicos do transformador pode eliminar, essencialmente, as restrições térmicas associadas à isolação celulósica, provendo uma solução econômica para aperfeiçoar o uso de transformadores de potência, aumentando a sua confiabilidade operacional. Adicionalmente, à aplicação de sensores de fibra óptica, em substituição aos sensores de imagem térmica no monitoramento das temperaturas internas do transformador, se apresentam como importante opção na definição do equacionamento do comportamento do transformador sob o ponto de vista térmico.