1,721,101 research outputs found
Single crystals of electronic materials: Growth and properties
No full textSingle Crystals of Electronic Materials: Growth and Properties is a complete overview of the state-of-the-art growth of bulk semiconductors. It is not only a valuable update on the body of information on crystal growth of well-established electronic materials, such as silicon, III-V, II-VI and IV-VI semiconductors, but also includes chapters on novel semiconductors, such as wide bandgap oxides like ZnO, Ga2, O3, In2, O3, Al2, O3, nitrides (AIN and GaN), and diamond. Each chapter focuses on a specific material, providing a comprehensive overview that includes applications and requirements, thermodynamic properties, schematics of growth methods, and more
Bulk Crystal Growth of Semiconductors: An Overview
No full textThe development of many new electronic devices is strictly connected with the availability of materials in single-crystalline form, with low density of crystallographic defects and specific electrical, magnetic, optical, chemical, and mechanical properties. These high-quality single crystals can be used either as substrates for the epitaxial growth of complicated multilayer structures or directly for the device manufacture. In the latter case, the active region of the device is obtained via dopant diffusion into the bulk material, surface oxidation, or metallization. One example is provided by polycrystalline Si solar cells, while infrared lasers, modulators, and detectors for optical telecommunications provide examples of complex epitaxial structures on high-quality InP or GaAs substrates. The need for high-quality semiconductor single crystals has triggered the development of suitable growth processes by which the composition, the structure, as well as the physical properties of a given semiconducting material may be accurately controlled. Different bulk growth technologies have been applied in order to obtain large single crystals of semiconducting materials: melt growth, solution growth, and vapor transport. The thermodynamical properties and the desired characteristics of the semiconductor to be grown actually decide what approach is most convenient. This chapter reviews the theoretical basis of the crystal growth processes and the most important crystal growth techniques. Examples of growth techniques developed in view of specific semiconductors are also reported
Wide Voltage Range Dual Active Bridge PV Retrofit Storage System
No full textThis paper presents a storage system integration on the photovoltaic module side of a traditional grid-connected PV plant. The proposed retrofit application is based on a wide voltage range Dual Active Bridge topology, used as bidirectional DC/DC converter. Wide voltage operation capability at PV side is required to allow the integration of the retrofit storage system on a broader range of existing PV plants, characterized by different PV string operating voltage and commercial grid-connected inverters. Dual Active Bridge topology was chosen as a galvanically-insulated bidirectional single stage conversion stage to interface storage batteries to the PV side of the existing photovoltaic plant. The storage battery is charged during the overproduction of the PV plant and the storage system sustains the end-user domestic loads when solar irradiation is insufficient. The proper operation of the commercial inverter, the design and control strategy of the whole system showed the effectiveness of the proposed solution. A full-size 3.2kW converter prototype was manufactured and experimental validation was carried out
"La questione dell’equità scolastica in Italia. Analisi delle performance in scienze dei quindicenni della scuola secondaria superiore" Working paper N.26 (3/2010), Fondazione Giovanni Agnelli
No full textWorking paper N.26 (3/2010),
Fondazione Giovanni Agnelli
Disponibile al link:
http://www.fga.it/uploads/media/L._Benadusi__R._Fornari__O._Giancola__La_questione_dell_equita_scolastica_in_Italia_-_FGA_WP26.pd
Deep level investigation In Fe-doped semi-insulating indium phosphide crystals
No full textIt has recently been reported that high-resistivity Fe-doped InP wafers can present very different compensation conditions. This gives rise to different mobility and conductivity characteristics. The high-resistivity InP samples can basically be assigned to three categories: (A) samples with high mobilities and thermal activation energies ≈ 0.60 eV; (B) samples with intermediate mobilities and activation energies below 0.60 eV; (C) samples with low mobilities and activation energies around 0.40 eV. Some reasons at the basis of the different physical properties exhibited by Fe-doped InP have already been discussed. In this work, new characterization techniques were applied in order to investigate other deep levels beside the main deep level due to iron
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