Semiconductor Crystal
Mostrando 1-12 de 31 artigos, teses e dissertações.
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1. Study of the Nb2O5 Insertion in ZnO to Dye-sensitized Solar Cells
Dye-sensitized solar cells (DSSC) have received much attention as an alternative to silicon-based solar cells, due to various advantages. Zinc oxide (ZnO) is an n-type semiconductor employed as photoanode on DSSC. The decrease of charge recombination is an efficient strategy capable of improving the photovoltaic performance of the device. In this perspective
Mat. Res.. Publicado em: 01/07/2019
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2. Influencia de los tratamientos térmicos en recubrimientos anódicos nanotubulares de TiO2
ABSTRACT TiO2 is a semiconductor widely used in heterogeneous photocatalysis processes for water decontamination. Several studies indicate that ordered nanostructures in anatase phase improve the photocatalytic properties with respect to other morphologies and crystal structures of TiO2. The aim of the present work is to evaluate the influence of different t
Matéria (Rio J.). Publicado em: 19/07/2018
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3. Band Structure, Charge Distribution and Optical Properties of AlPxSb1-x Ternary Semiconductor Alloys
The present contribution studies on the composition dependence of the electronic and optical properties of the zinc-blende alloy system AlPxSb1-x. The calculations are performed using a pseudopotential approach under the virtual crystal approximation. Features such as electronic band structure, energy band-gaps, refractive index, dielectric constants and val
Mat. Res.. Publicado em: 21/05/2018
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4. Synthesis and Crystal Structure of Three New Quaternary Compounds in the system Cu-Mn-III-Se3 (III = Al, Ga, In)
Chalcogenide alloys CuMnAlSe3, CuMnGaSe3 and CuMnInSe3, new members of the semiconductor system I-II-III-VI3, were synthetized and structurally characterized by the Rietveld method using X-ray powder diffraction data. All compounds crystallize in the tetragonal space group P4 2c (Nº 112) with a CuFeInSe3-type structure.
Mat. Res.. Publicado em: 05/02/2018
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5. HIGH PRESSURE BEHAVIOR OF CRYSTALLINE DIHYDROXYLAMMONIUM 5,5'-BISTETRAZOLE-1,1'-DIOLATE: FIRST-PRINCIPLES STUDY
Density functional theory (DFT) periodic calculations were performed to study the geometrical and electronic structures of energetic compound dihydroxylammonium 5,5'-bistetrazole-1,1'-diolate (TKX-50) under the pressure ranging from 0 to 400 GPa. The optimized crystal structure by the local density approximation (LDA) with CA-PZ functional matches well with
Quím. Nova. Publicado em: 2017-10
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6. Desenvolvimento do cristal semicondutor de iodeto de mercúrio para aplicação como detector de radiação / Development of the mercury iodide semiconductor crystal for application as a radiation detector
In this work, the establishment of a technique for HgI growth and preparation of crystals, for use as room temperature radiation semiconductor detectors is described. Three methods of crystal growth were studied while developing this work: (1) Physical Vapor Transport (PVT); (2) Saturated Solution of HgI2, using two different solvents; (a) dimethyl sulfoxide
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 11/07/2011
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7. Desenvolvimento de processos de eletrodos de porta (TaN e TiN) para dispositivos MOS / Process development of gate electrodes (TiN and TaN) for MOS devices
Tantalum nitride (TaN) and titanium nitride (TiN) films have been obtained by DC sputtering, using different nitrogen flow (10 - 80 sccm) and power (500 - 1500 W), in a nitrogen (N2)/argon (Ar) ambient on Si (100) substrates. The N2/Ar ratio in gas mixture and power effects on structural and electrical properties of TaN and TiN films were investigated by sca
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 01/07/2011
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8. Efeitos de campo cristalino e rattling modes em skutterudites / Crystal field and rattling mode effects in skutterudites
This thesis addresses the general problem of crystall field effects and rattling modes in skut- terudite compounds. It employs, predominantly, the electron spin resonance technique (ESR or EPR, in the classical literature) aiming to probe the local point symmetry of the electronic states associated to the rare earth ions and the inohomogenities implied by th
Publicado em: 2010
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9. Estudo estrutural de nanossistemas semicondudores e semicondutores implantados por difração de raios-X de n-feixes / Structural study of semiconductors nanosystems and implanted semiconductors by means of n-beams X-ray diffraction
In this paper, X-ray multiple diffraction (MD) associated with the advantages of synchrotron radiation appears as a high-resolution microprobe and it is used to obtain relevant contributions to the study of structural properties of semiconductor materials, as they present themselves nanosystems epitaxial or implanted with ions. The study and detection of neg
Publicado em: 2010
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10. ESTUDO DE PRIMEIROS PRINCíPIOS DE DEFEITOS NATIVOS EM MONÓXIDO DE BERÍLIO / FIRST PRINCIPLES STUDY OF NATIVE DEFECTS IN BERYLLIUM MONOXIDE
The present thesis shows a study of native defects (vacancies and antisites) in Beryllium Monoxide (BeO) by means of first principle calculations within Density Functional Theory (DFT). We made use of Local Density Aproximation (LDA) in order to approach correlation and shift term, and ultrasoft pseudopotentials in order to describe the electron-core interac
Publicado em: 2009
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11. Filtros acústicos em cristais fonônicos
In this work, we have studied the acoustic phonon wave propagation within the periodic and quasiperiodic superlattices of Fibonacci type. These structures are formed by phononic crystals, whose periodicity allows the raise of regions known as stop bands, which prevent the phonon propagation throughout the structure for specific frequency values. This p
Publicado em: 2009
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12. Caracterización eléctrica de películas delgadas de Al2O3 depositadas sobre GaAs por la técnica de rocío pirolítico
Electrical characteristics of thin films of aluminum oxide prepared by spray pyrolysis were studied. The films were prepared from solution onto single crystal GaAs (100) substrates at temperatures from 300°C to 600°C. The electrical characteristics of these films as a function of the substrate temperature were determined from the capacitance and current ve
Matéria (Rio de Janeiro). Publicado em: 2008-03