Light-induced change of Si-H bond absorption in hydrogenated amorphous silicon

Device-quality a-Si:H films were prepared by glow discharge CVD with pure or H-diluted silane as well as by hot-wire CVD. The hydrogen content was varied from similar to 2 to 15 at. %. The Si-H bond absorption and its light-soaking-induced changes were studied by IR and differential IR absorption spectroscopes. The results indicate that the more stable sample exhibits an increase of the absorption at wave number similar to 2000 cm(-1), and the less stable one exhibits a decrease at similar to 2040 cm(-1) and an increase at similar to 1880 cm(-1).

Light-excited structural instability of a-Si : H.

With the accumulation of experimental data, it has been recognized by many that the light-induced metastable change of a-Si:H, Staebler-Wronski effect (SWE), may be related to a structural instability of the whole a-Si:H network. However, direct evidence of such a structural change is still lacking. In the present paper, the efforts of our laboratory in this direction will be reviewed, including the light-induced changes of Si-H bond absorption, low frequency dielectric response, and an apparent photo-dilation effect.

High quality hydrogenated amorphous silicon films with significantly improved stability

High quality hydrogenated amorphous silicon (a-Si:H) films have been prepared by a simple "uninterrupted growth/annealing" plasma enhanced chemical vapor deposition (PECVD) technique, combined with a subtle boron-compensated doping. These a-Si:H films possess a high photosensitivity over 10(6), and exhibit no degradation in photoconductivity and a low light-induced defect density after prolonged illumination. The central idea is to control the growth conditions adjacent to the critical point of phase transition from amorphous to crystalline state, and yet to locate the Fermi level close to the midgap. Our results show that the improved stability and photosensitivity of a-Si:H films prepared by this method can be mainly attributed to the formation of a more robust network structure and reduction in the precursors density of light-induced metastable defects.

Structural properties of polycrystalline silicon films formed by pulsed rapid thermal processing

A novel pulsed rapid thermal processing (PRTP) method has been used for realizing the solid-phase crystallization of amorphous silicon films prepared by PECVD. The microstructure and surface morphology of the crystallized films are investigated by X-ray diffraction (XRD) and atomic force microscopy (AFM). The results indicate that this PRTP is a suitable post-crystallization technique for fabricating large-area polycrystalline silicon films with good structural qualities such as large grain size, small lattice microstain and smooth surface morphology on low-cost substrate.

The effect of low temperature GaAs nucleation on the growth of GaN on Silicon (001) during MOVPE process

High quality cubic GaN was grown on Silicon (001) by metalorganic vapor phase epitaxy (MOVPE) using a GaAs nucleation layer grown at low temperature. The influence of various nucleation conditions on the GaN epilayers' quality was investigated. We found that the GaAs nucleation layer grown by atomic layer epitaxy (ALE) could improve the quality of GaN films by depressing the formation of mixed phase. Photoluminescence (PL) and X-ray diffraction were used to characterize the properties of GaN epilayers. High quality GaN epilayers with PL full width at half maximum (FWHM) of 130meV at room temperature and X-ray FWHM of 70 arc-min were obtained by using 10-20nm GaAs nucleation layer grown by ALE.

Preliminary Report of the 1 field season at Gubbio.:Malone, C.A.T. and S.K.F. Stoddart,

Xerox circulation to sponsors. Cambridge University.

Preliminary report of the 1984 field season at Gubbio.,

Malone, C.A.T., et al., in Xerox circulation to sponsors. 1984. Cambridge University.

Provisional report. 1987 Season. Gubbio Project

Stoddart, S.K.F. and C. Malone,. Xerox circulation to sponsors. 1987.

1988 Season. Cambridge Gozo Project.

Stoddart, S.K.F.M., C and Trump. D, Provisional report. Xerox circulation to sponsors. 1988.

Preliminary Report. Post Excavation Work. Gubbio Project.

Stoddart, S.K.F. and C.A.T. Malone, Xerox circulation to sponsors. 1988.

Kids Club, Un modelo de negocio exitoso del Sector del Calzado en Colombia

“Los modelos de negocio describen las bases sobre las cuales una empresa, crea, proporciona y capta valor”. Osterwalder, Alexander. (2010). Kids Club es una empresa manufacturera de calzado para niños catalogada por PROEXPORT como una de las mejores empresas Colombianas dentro del sector; y una de las pocas empresas que en menos de 10 años logro exportar sus productos a mercados internacionales a partir de técnicas administrativas empíricas. A través del siguiente estudio de caso, se pretende describir el modelo de negocio de la empresa; identificando sus segmentos de mercado, estructura de cadena de valor y mecanismos de generación de ventas con el objetivo de identificar sus factores críticos de éxito y proponer nuevas alternativas para que se mantenga como líder del sector, en el entorno empresarial actual.

Comunitats de pr??ctica o l'aprenentatge compartit

Resumen basado en el de la publicaci??n

Apresentação

Este trabalho foi apresentado, inicialmente, em Fevereiro de 1997, como monografia, ao Curso de História da Universidade Estadual do Ceará - Brasil, sendo exigência parcial para a obtenção da Licenciatura Plena em História1. Uma observação pertinente diz respeito a que, em princípio, ele foi pensado como trabalho acadêmico, mas cuja divulgação — ainda que de maneira amadorística, via xerox — pudesse oportunamente atingir alguns dos museus cearenses, sempre em defasagem com a produção e com as discussões no âmbito da Museologia. Daí existirem momentos de revisão bibliográfica e de claras e propositais alfinetadas em relação à acomodação reinante em alguns desses museus. A proposta de publicação em Portugal, além de uma agradável surpresa, trouxe a questão da adaptação a um público mais abrangente e inserido em outra realidade. Optamos, no entanto, por manter o texto original com mínimas alterações2 e acréscimos explicativos. Que a troca de experiências se faça valer como contribuição aos debates museológicos. Ao primeiro contato com a Museologia, as possibilidades de pesquisa na área e o desvendar de uma vasta gama de bens patrimoniais passíveis de se estudar enquanto registro histórico, tornamo-nos totalmente cativos e, desde então, todos os esforços têm sido feitos no sentido de avançar nesta área, mercê das dificuldades que se apresentam.

Utvärdering av digitala provtryckssystem

Six different Digital Proofing Systems from three different techniques have been evaluated as totechnique, printing quality, economy and usability. Digital proof from two paper qualities, coatedand uncoated, has been compared with references printed in offset, to see how good they match eachother. Only two Proofing Systems manage to print on reference paper. The other Proofing Systemsuse special paper for digital proof.Measurements and visuell judgement show that the Digital Proofing Systems visualise referencepictures with quite good quality. Proof optimised for coated paper visualise the colours with goodresult. Proof optimised for uncoated paper shows higher quality than the references, which depends onthe surface of the proofing paper. Comparison between reference paper and proofing paper has takenplace as to differences in colour and paper quality.The Digital Proofing Systems are fully automatic, which demand a quite comprised education forcorrect handling. The purchase price and printing costs vary considerably between the ProofingSystems.

Färgstyrning av kontorsutrustning

Color management has become more common now than ever in the graphic trade. Calibration andcharcterization are words that are mentioned very often when it comes to controlling colors andwhen you want a printed picture to look the same as an original photograph. The problem is thatthere are not so many people that has the knowlegde about this subject. Even if a printer supportscolor management it is not sure that the result is going to be satisfied and that a printed picture isgoing to look the same as the original.The printers which were used were Hp DeskJet 970 Cxi, Xerox Docu Color 12 and AgfaChromapress 50i. The theory of color, colour management and the equipment which were usedare described in the first stage. The second stage describes calibration and characterization ofmonitors, scanners and printers. Finally the result of created ICC-profiles is set by visual comparisionof a photographs original colours and a scanned and printed photograph.The results of calibration and characterization were varying a lot. Agfa Chromapress 50i was theonly printer which could produce a succesful calibration. Agfa Chromapress 50i and XeroxDocuColor 12 gave the best results when comparing original photographs with printed pictures ifthey were separated with ICC-profiles. ICC-profiles created for Hp DeskJet 970 Cxi achievedundesirable effects. This was the only printer that gave a bad result both with and without ICCprofiles.The reason for this miserable result can depend on the printers unability to fully supportcolor management.