气相传输平衡法在（11-20）面蓝宝石上制备γ铝酸锂膜

为了寻找可能替代蓝宝石作为氮化镓外延的新型衬底，通过48h的气相传输平衡，分别在1000℃、1030℃、1050℃、1070℃和1100℃制备了一层单相多晶的γ铝酸锂膜。X射线衍射和扫描电镜分别用于表征膜的物相、取向和表面形貌。结果显示，γ铝酸锂择优取向的好坏取决于气相平衡传输温度，在1050℃制备的γ铝酸锂具有高度的[100]择优取向；在γ铝酸锂（001）面上的双轴拉应力可能有助于[100]择优取向的形成；γ铝酸锂晶粒表面裂纹的方向一致性与其择优取向紧密相关。上述结果表明在合适的工艺条件下，气相传输平衡

A Lei 11.638/2007 e a Harmonização de Práticas Contábeis em Empresas Multinacionais: Um Estudo de Caso sobre a Vale

O mundo transforma-se constantemente, assim como tudo o que nele está inserido. A evolução da economia possibilitou uma maior integração do mercado financeiro, tornando o ambiente de negócios único e global. É cada vez mais comum o ingresso de recursos estrangeiros nos mercados de capitais nacionais, bem como fusões e aquisições entre companhias de países distintos e com características próprias. Essas empresas, por sua vez, esforçam-se em adotar normas que atendam aos stakeholders, sem perder a obrigatoriedade de apresentar suas demonstrações contábeis em conformidade com as características do país em que estão sediadas. Com a unificação dos países da Europa em um único bloco econômico, vislumbrou-se a possibilidade de desenvolver normas que pudessem ser compreendidas e interpretadas pelos diversos usuários destas demonstrações contábeis, em qualquer lugar do globo. Assim criadas, as normas de IFRS International Financial Reporting Standards buscaram a redução de diferenças nas metodologias contábeis e na forma com que são divulgadas em cada país, permitindo a comparabilidade e evidenciação das informações ao mercado. O IFRS, atualmente, já é adotado por mais de 100 países no mundo. No Brasil, em 28 de dezembro de 2007, promulgou-se a Lei 11.638 eliminando barreiras regulatórias que impediam a inserção total das empresas brasileiras no processo de convergência contábil internacional e aproximando sua legislação referente às normas contábeis às do mundo globalizado. O objeto do presente estudo é apresentar as principais mudanças decorrentes dessa adoção e seus impactos na contabilidade das empresas brasileiras, tomando como exemplo a empresa Vale, multinacional brasileira com alto volume diário de negociações de suas ações em Bolsa de Valores, grande parte de investidores estrangeiros. Os assuntos controversos, definições e entendimentos que ainda serão deliberados até 2010, evidenciam que não houve tempo hábil para a discussão e preparação das empresas, do fisco, de profissionais do mundo empresarial e acadêmico, dos contadores e auditores, bem como dos órgãos reguladores. Apesar das aparentes dificuldades, o Brasil deu um grande salto na qualidade das informações prestadas e aproxima-se dos grandes investidores globais, capacitando-se para receber recursos que possibilitem o seu crescimento econômico e o seu papel no cenário mundial.

Hydrogenated amorphous silicon and silicon nitride deposited at less than 100° C by ECR-PECVD for thin film transistors

A systematic study has been made of the growth of both hydrogenated amorphous silicon (a-Si:H) and silicon nitride (a-SiN) by electron cyclotron resonance plasma enhanced chemical vapour deposition (ECR-PECVD). In the case of a-SiN, helium and nitrogen gas is injected into the system such that it passes through the resonance zone. These highly ionised gases provide sufficient energy to ionise the silane gas, which is injected further downstream. It is demonstrated that a gas phase reaction occurs between the silane and nitrogen species. It is control of the ratio of silane to nitrogen in the plasma which is critical for the production of stoichiometric a-SiN. Material has been produced at 80°C with a Si:N ratio of 1:1.3 a breakdown strength of ∼6 MV cm-1 and resistivity of > 1014 Ω cm. In the case of a-Si:H, helium and hydrogen gas is injected into the ECR zone and silane is injected downstream. It is shown that control of the gas phase reactions is critical in this process also. a-Si:H has been deposited at 80 °C with a dark conductivity of 10-11 Ω-1 cm-1 and a photosensitivity of justbelowl 4×104. Such materials are suitable for use in thin film transistors on plastic substrates.

High bit rate quantum key distribution with 100 dB security

We report the operation of a gigahertz clocked quantum key distribution system featuring high composable and quantifiable security while maintaining more than 1 Mbit/s secure key rate over a 50 km quantum channel. © OSA 2013.

100 Gigabit ethernet transmission enabled by carrierless amplitude and phase modulation using QAM receivers

Simulations have investigated single laser 100G Ethernet links enabled by CAP-16 using QAM receivers that not only lower significantly system timing jitter sensitivity but also outperform PAM and standard CAP in terms of power margin. © 2013 OSA.

PASSIVATION OF THE INP(100) SURFACE USING (NH4)(2)S-X

InP(100) surface treated with (NH4)(2)S-x has been investigated by using photoluminescence(PL), Auger electron spectroscopy and X-ray photoelectron spectroscopy. It is found that PL intensity increased by a factor of 3.3 after (NH4)(2)S-x passivation and the sulfur remained on the surface only bonded to indium, not to phosphorus. This suggests that the sulfur atoms replace the phosphorus atoms on the surface and occupy the phosphorus vacancies.

PHOTOEMISSION-STUDIES OF K-PROMOTED NITRIDATION OF INP(100) SURFACE USING SYNCHROTRON-RADIATION

The effect of molecular nitrogen exposure on the surfaces of InP(100) modified by potassium overlayers is investigated by core-level and valence-band photoemission spectroscopy using Synchrotron radiation. In comparison with InP(110) surface, we found the promotion is much stronger for InP(100) surface due to the central role of surface defects in the promotion; furthermore, in contrast with K-promoted oxidation of InP(100) where the bonding is observed between indium and oxygen, indium atoms did not react directly with nitrogen atoms during the K-promoted nitridation of InP(100).

Growth of Space Ordered on GaAs（100） Vicinal 1.3μm InAs Quantum Dots Substrates by MOCVD

Space ordered 1.3μm self-assembled InAs QDs are grown on GaAs（100） vicinal substrates by MOCVD. Photoluminescence measurements show that the dots on vicinal substrates have a much higher PL intensity and a narrower FWHM than those of dots on exact substrates, which indicates better material quality. To obtain 1.3μm emissions of InAs QDs, the role of the so called InGaAs strain cap layer （SCL） and the strain buffer layer （SBL） in the strain relaxation process in quantum dots is studied. While the use of SBL results only in a small change of emission wavelength,SCL can extend the QD＇s emission over 1.3μm due to the effective strain reducing effect of SCL.

Si(100)衬底上n-3C-SiC／p-Si异质结构研究

利用LPCVD方法在Si(100)衬底上获得了3C-SiC外延膜，扫描电子显微镜(SEM)研究表明3C-SiC／p—Si界面平整、光滑，无明显的坑洞形成。研究了以In和Al为接触电极的3C-SiC／p—Si异质结的I—V，C-V特性及I—V特性的温度依赖关系，比较了In电极的3C-SiC／p—Si异质结构和以SiGe作为缓冲层的3C-SiC／SiGe／p—Si异质结构的I—V特性，实验发现引入SiGe缓冲层后，器件的反向击穿电压由40V提高到70V以上。室温下A1电极3C-SiC／p—Si二极管的最大反向击穿电压接近100V，品质因子为1．95。

提高（100）晶向磷化铟单晶的成晶率和质量的研究

通过对高压液封直接法单晶生长过程的热传输和影响熔体温度起伏的几个关键因素的分析，研究适全生长（100）晶向磷化铟单晶的热场系统，有效地降低了孪晶产生的几率，重复地生长出了整锭掺硫和掺铁的、直径为50mm和76mm的（100）磷化铟单晶。测试结果表明我们生长（100）磷化铟单晶的热场在生长过程中使晶锭保持较为平坦的固液界面，可稳定地获得具有低的缺陷密度和良好的电学均匀性的高质量磷化铟单晶材料。

Heteroepitaxial Growth and Heterojunction Characteristics of Voids-Free n-3C-SiC on p-Si(100)

Highly oriented voids-free 3C-SiC heteroepitaxial layers are grown on φ50mm Si (100) substrates by low pressure chemical vapor deposition (LPCVD). The initial stage of carbonization and the surface morphology of carbonization layers of Si(100) are studied using reflection high energy electron diffraction (RHEED) and scanning electron microscopy (SEM). It is shown that the optimized carbonization temperature for the growth of voids-free 3S-SiC on Si (100) substrates is 1100 ℃. The electrical properties of SiC layers are characterized using Van der Pauw method. The I-V, C-V, and the temperature dependence of I-V characteristics in n-3C-SiC-p-Si heterojunctions with AuGeNi and Al electrical pads are investigated. It is shown that the maximum reverse breakdown voltage of the n-3C-SiC-p-Si heterojunction diodes reaches to 220V at room temperature. These results indicate that the SiC/Si heterojunction diode can be used to fabricate the wide bandgap emitter SiC/Si heterojunction bipolar transistors (HBT's).

Raman Investigatins of 3C-SiC Films Grown on Si (100) and Sapphire (0001) by LPCVD

The Raman measurements have been performed with the back-scattering geometry on the SiC films grown on Si(100) and sapphire (0001) by LPCVD. Typical TO and LO phonon peaks of 3C-SiC were observed for all the samples grown on Si and apphire substrates, indicating the epilayers are 3C-SiC polytype. Using a free-standing 3C-SiC film removed from Si(100) as a free-stress sample, the stresses of 3C-SiC on Si(100) and sapphire (0001) were estimated according to the shift of TO and LO phonons.

立方相 Al_xGa_(1-x)N/GaAs(100)的MOVCD外延生长

利用MOCVD生长技术在GaAs(100)衬底上生长了高质量的立方相AlGaN薄膜。通过光致发光（PL）、扫描电镜（SEM）分析了不同NH_3流量、不同生长温度对AlGaN外延层的结晶质量和表面形貌的影响。发现相对高的NH_3流量和相对高的生长温度可以提高AlGaN外延层的结晶质量。