Sample records for solid encapsulated semiconductor

  1. Solid-Phase Immunoassay of Polystyrene-Encapsulated Semiconductor Coreshells for Cardiac Marker Detection

    Sanghee Kim


    Full Text Available A solid-phase immunoassay of polystyrene-encapsulated semiconductor nanoparticles was demonstrated for cardiac troponin I (cTnI detection. CdSe/ZnS coreshells were encapsulated with a carboxyl-functionalized polystyrene nanoparticle to capture the target antibody through a covalent bonding and to eliminate the photoblinking and toxicity of semiconductor luminescent immunosensor. The polystyrene-encapsulated CdSe/ZnS fluorophores on surface-modified glass chip identified cTnI antigens at the level of ~ng/mL. It was an initial demonstration of diagnostic chip for monitoring a cardiovascular disease.

  2. A novel approach for the fabrication of all-inorganic nanocrystal solids: Semiconductor matrix encapsulated nanocrystal arrays

    Moroz, Pavel

    Growing fossil fuels consumption compels researchers to find new alternative pathways to produce energy. Along with new materials for the conversion of different types of energy into electricity innovative methods for efficient processing of energy sources are also introduced. The main criteria for the success of such materials and methods are the low cost and compelling performance. Among different types of materials semiconductor nanocrystals are considered as promising candidates for the role of the efficient and cheap absorbers for solar energy applications. In addition to the anticipated cost reduction, the integration of nanocrystals (NC) into device architectures is inspired by the possibility of tuning the energy of electrical charges in NCs via nanoparticle size. However, the stability of nanocrystals in photovoltaic devices is limited by the stability of organic ligands which passivate the surface of semiconductors to preserve quantum confinement. The present work introduces a new strategy for low-temperature processing of colloidal nanocrystals into all-inorganic films: semiconductor matrix encapsulated nanocrystal arrays (SMENA). This methodology goes beyond the traditional ligand-interlinking scheme and relies on the encapsulation of morphologically-defined nanocrystal arrays into a matrix of a wide-band gap semiconductor, which preserves optoelectronic properties of individual nanoparticles. Fabricated solids exhibit excellent thermal stability, which is attributed to the heteroepitaxial structure of nanocrystal-matrix interfaces. The main characteristics and properties of these solids were investigated and compared with ones of traditionally fabricated nanocrystal films using standard spectroscopic, optoelectronic and electronic techniques. As a proof of concept, we. We also characterized electron transport phenomena in different types of nanocrystal films using all-optical approach. By measuring excited carrier lifetimes in either ligand-linked or

  3. Screening Plastic-Encapsulated Solid-State Devices

    Buldhaupt, L.


    Suitability of plastic-encapsulated solid-state electronic devices for use in spacecraft discussed. Conclusion of preliminary study was plasticencapsulated parts sufficiently reliable to be considered for use in lowcost equipment used at moderate temperature and low humidity. Useful to engineers as guides to testing or use of plastic encapsulated semiconductors in severe terrestrial environments.

  4. Mercuric iodide semiconductor detectors encapsulated in polymeric resin

    Martins, Joao F. Trencher; Santos, Robinson A. dos; Ferraz, Caue de M.; Oliveira, Adriano S.; Velo, Alexandre F.; Mesquita, Carlos H. de; Hamada, Margarida M., E-mail: [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Disch, Christian; Fiederle, Michael [Albert-Ludwigs Universität Freiburg - UniFreibrug, Freiburg Materials Research Center - FMF, Freiburg (Germany)


    The development of new semiconductor radiation detectors always finds many setback factors, such as: high concentration of impurities in the start materials, poor long term stability, the surface oxidation and other difficulties discussed extensively in the literature, that limit their use. In this work was studied, the application of a coating resin on HgI2 detectors, in order to protect the semiconductor crystal reactions from atmospheric gases and to isolate electrically the surface of the crystals. Four polymeric resins were analyzed: Resin 1: 50% - 100%Heptane, 10% - 25% methylcyclohexane, <1% cyclohexane; Resin 2: 25% - 50% ethanol, 25% - 50% acetone, <2,5% ethylacetate; Resin 3: 50% - 100% methylacetate, 5% - 10% n-butylacetate; Resin 4: 50% - 100% ethyl-2-cyanacrylat. The influence of the polymeric resin type used on the spectroscopic performance of the HgI{sub 2} semiconductor detector is, clearly, demonstrated. The better result was found for the detector encapsulated with Resin 3. An increase of up to 26 times at the stability time was observed for the detectors encapsulated compared to that non-encapsulated detector. (author)

  5. Analysis of field usage failure rate data for plastic encapsulated solid state devices


    Survey and questionnaire techniques were used to gather data from users and manufacturers on the failure rates in the field of plastic encapsulated semiconductors. It was found that such solid state devices are being successfully used by commercial companies which impose certain screening and qualification procedures. The reliability of these semiconductors is now adequate to support their consideration in NASA systems, particularly in low cost systems. The cost of performing necessary screening for NASA applications was assessed.

  6. All-polymer organic semiconductor laser chips: Parallel fabrication and encapsulation

    Vannahme, Christoph; Klinkhammer, Sönke; Christiansen, Mads Brøkner


    Organic semiconductor lasers are of particular interest as tunable visible laser light sources. For bringing those to market encapsulation is needed to ensure practicable lifetimes. Additionally, fabrication technologies suitable for mass production must be used. We introduce all-polymer chips...... comprising encapsulated distributed feedback organic semiconductor lasers. Several chips are fabricated in parallel by thermal nanoimprint of the feedback grating on 4? wafer scale out of poly(methyl methacrylate) (PMMA) and cyclic olefin copolymer (COC). The lasers consisting of the organic semiconductor...... tris(8- hydroxyquinoline) aluminum (Alq3) doped with the laser dye 4-dicyanomethylene-2- methyl-6-(p-dimethylaminostyril)-4H-pyrane (DCM) are hermetically sealed by thermally bonding a polymer lid. The organic thin film is placed in a basin within the substrate and is not in direct contact to the lid...

  7. Optoelectronic Properties of Semiconductor Quantum Dot Solids for Photovoltaic Applications.

    Chistyakov, A A; Zvaigzne, M A; Nikitenko, V R; Tameev, A R; Martynov, I L; Prezhdo, O V


    Quantum dot (QD) solids represent a new type of condensed matter drawing high fundamental and applied interest. Quantum confinement in individual QDs, combined with macroscopic scale whole materials, leads to novel exciton and charge transfer features that are particularly relevant to optoelectronic applications. This Perspective discusses the structure of semiconductor QD solids, optical and spectral properties, charge carrier transport, and photovoltaic applications. The distance between adjacent nanoparticles and surface ligands influences greatly electrostatic interactions between QDs and, hence, charge and energy transfer. It is almost inevitable that QD solids exhibit energetic disorder that bears many similarities to disordered organic semiconductors, with charge and exciton transport described by the multiple trapping model. QD solids are synthesized at low cost from colloidal solutions by casting, spraying, and printing. A judicious selection of a layer sequence involving QDs with different size, composition, and ligands can be used to harvest sunlight over a wide spectral range, leading to inexpensive and efficient photovoltaic devices.

  8. Magnetic Damping of Solid Solution Semiconductor Alloys

    Szofran, Frank R.; Benz, K. W.; Croell, Arne; Dold, Peter; Cobb, Sharon D.; Volz, Martin P.; Motakef, Shariar


    The objective of this study is to: (1) experimentally test the validity of the modeling predictions applicable to the magnetic damping of convective flows in electrically conductive melts as this applies to the bulk growth of solid solution semiconducting materials; and (2) assess the effectiveness of steady magnetic fields in reducing the fluid flows occurring in these materials during processing. To achieve the objectives of this investigation, we are carrying out a comprehensive program in the Bridgman and floating-zone configurations using the solid solution alloy system Ge-Si. This alloy system has been studied extensively in environments that have not simultaneously included both low gravity and an applied magnetic field. Also, all compositions have a high electrical conductivity, and the materials parameters permit reasonable growth rates. An important supporting investigation is determining the role, if any, that thermoelectromagnetic convection (TEMC) plays during growth of these materials in a magnetic field. TEMC has significant implications for the deployment of a Magnetic Damping Furnace in space. This effect will be especially important in solid solutions where the growth interface is, in general, neither isothermal nor isoconcentrational. It could be important in single melting point materials, also, if faceting takes place producing a non-isothermal interface. In conclusion, magnetic fields up to 5 Tesla are sufficient to eliminate time-dependent convection in silicon floating zones and possibly Bridgman growth of Ge-Si alloys. In both cases, steady convection appears to be more significant for mass transport than diffusion, even at 5 Tesla in the geometries used here. These results are corroborated in both growth configurations by calculations.

  9. Shea butter solid nanoparticles for curcumin encapsulation: Influence of nanoparticles size on drug loading

    Hajj Ali, Hassan; Michaux, Florentin; Bouelet Ntsama, Isabelle Sandrine; Durand, Pierrick; Jasniewski, Jordane; Linder, Michel


    International audience; In the present work, shea butter solid lipid nanoparticles (SLN) were prepared by sonication using nonionic surfactants as stabilizers without organic solvent. The mixture design methodology enabled to control particles size from 50?nm to more than 1?µm according to the mixture composition. Then, curcumin, a natural polyphenol, has been encapsulated in nanoparticles with a wide range of diameters (50–230?nm) and the encapsulation efficiency has been related to the part...

  10. Nanoscale doping of compound semiconductors by solid phase dopant diffusion

    Ahn, Jaehyun, E-mail:; Koh, Donghyi; Roy, Anupam; Banerjee, Sanjay K., E-mail: [Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78712 (United States); Chou, Harry [Materials Science and Engineering Program, University of Texas at Austin, Austin, Texas 78712 (United States); Kim, Taegon [Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78712 (United States); Semiconductor R& D Center, Samsung Electronics Corporation, 1 Samsungjeonja-ro, Hwasung, Kyounggi 445-330 (Korea, Republic of); Song, Jonghan [Advanced Analysis Center, Korea Institute of Science and Technology, Cheongryang, P.O. Box 131, Seoul 130-650 (Korea, Republic of)


    Achieving damage-free, uniform, abrupt, ultra-shallow junctions while simultaneously controlling the doping concentration on the nanoscale is an ongoing challenge to the scaling down of electronic device dimensions. Here, we demonstrate a simple method of effectively doping ΙΙΙ-V compound semiconductors, specifically InGaAs, by a solid phase doping source. This method is based on the in-diffusion of oxygen and/or silicon from a deposited non-stoichiometric silicon dioxide (SiO{sub x}) film on InGaAs, which then acts as donors upon activation by annealing. The dopant profile and concentration can be controlled by the deposited film thickness and thermal annealing parameters, giving active carrier concentration of 1.4 × 10{sup 18 }cm{sup −3}. Our results also indicate that conventional silicon based processes must be carefully reviewed for compound semiconductor device fabrication to prevent unintended doping.

  11. Nuclear magnetic relaxation studies of semiconductor nanocrystals and solids

    Sachleben, J. R. [Lawrence Berkeley Lab., CA (United States); California Univ., Berkeley, CA (United States). Dept. of Chemistry


    Semiconductor nanocrystals, small biomolecules, and {sup 13}C enriched solids were studied through the relaxation in NMR spectra. Surface structure of semiconductor nanocrystals (CdS) was deduced from high resolution {sup 1}H and {sup 13}C liquid state spectra of thiophenol ligands on the nanocrystal surfaces. The surface coverage by thiophenol was found to be low, being 5.6 and 26% for nanocrystal radii of 11.8 and 19.2 {angstrom}. Internal motion is estimated to be slow with a correlation time > 10{sup {minus}8} s{sup {minus}1}. The surface thiophenol ligands react to form a dithiophenol when the nanocrystals were subjected to O{sub 2} and ultraviolet. A method for measuring {sup 14}N-{sup 1}H J-couplings is demonstrated on pyridine and the peptide oxytocin; selective 2D T{sub 1} and T{sub 2} experiments are presented for measuring relaxation times in crowded spectra with overlapping peaks in 1D, but relaxation effects interfere. Possibility of carbon-carbon cross relaxation in {sup 13}C enriched solids is demonstrated by experiments on zinc acetate and L-alanine.

  12. In situ transmission electron microscopy of solid-liquid phase transition of silica encapsulated bismuth nanoparticles

    Hu, Jianjun; Hong, Yan; Muratore, Chris; Su, Ming; Voevodin, Andrey A.


    The solid-liquid phase transition of silica encapsulated bismuth nanoparticles was studied by in situ transmission electron microscopy (TEM). The nanoparticles were prepared by a two-step chemical synthesis process involving thermal decomposition of organometallic precursors for nucleating bismuth and a sol-gel process for growing silica. The microstructural and chemical analyses of the nanoparticles were performed using high-resolution TEM, Z-contrast imaging, focused ion beam milling, and X-ray energy dispersive spectroscopy. Solid-liquid-solid phase transitions of the nanoparticles were directly recorded by electron diffractions and TEM images. The silica encapsulation of the nanoparticles prevented agglomeration and allowed particles to preserve their original volume upon melting, which is desirable for applications of phase change nanoparticles with consistently repeatable thermal properties.

  13. Development of solid state moisture sensors for semiconductor fabrication applications

    Pfeifer, K.B.; Kelly, M.J.; Guilinger, T.R.; Peterson, D.W.; Sweet, J.N.; Tuck, M.R.


    We describe the design and fabrication of two types of solid state moisture sensors, and discuss the results of an evaluation of the sensors for the detection of trace levels of moisture in semiconductor process gases. The first sensor is based on surface acoustic wave (SAW) technology. A moisture sensitive layer is deposited onto a SAW device, and the amount of moisture adsorbed on the layer produces a proportional shift in the operating frequency of the device. Sensors based on this concept have excellent detection limits for moisture in inert gas (100 ppb) and corrosive gas (150 ppb in HCl). The second sensor is a simple capacitor structure that uses porous silicon as a moisture-sensitive dielectric material. The detection limits of these sensors for moisture in inert gas are about 700 ppb prior to HCl exposure, and about 7 ppm following HCl exposure.

  14. Tracer-Encapsulated Solid Pellet (TESPEL) Injection System for the TJ-II Stellarator

    Tamura, N. [National Institute for Fusion Science, Toki, Japan; McCarthy, K. J. [EURATOM-CIEMAT, Madrid, Spain; Hayashi, H. [National Institute for Fusion Science, Toki, Japan; Combs, Stephen Kirk [ORNL; Foust, Charles R [ORNL; Garcia, R. [Laboratory Nacional de Fusion, Madrid, Spain; Panadero, N. [CIEMAT, Laboratory Nacional de Fusion, Spain; Pawelec, E. [Opole University, Poland; Sanchez, J. Hernandez [Laboratory Nacional de Fusion, Madrid, Spain; Navarro, M. [CIEMAT, Laboratory Nacional de Fusion, Spain; Soleto, A. [CIEMAT, Laboratory Nacional de Fusion, Spain


    A tracer-encapsulated solid pellet (TESPEL) injection system for the TJ-II stellarator was recently developed. In order to reduce the time and cost for the development, we combined a TESPEL injector provided by National Institute for Fusion Science with an existing TJ-II cryogenic pellet injection system. Consequently, the TESPEL injection into the TJ-II plasma was successfully achieved, which was confirmed by several pellet diagnostics including a normal-incidence spectrometer for monitoring a tracer impurity behavior.

  15. Encapsulated triplet-triplet annihilation-based upconversion in the aqueous phase for sub-band-gap semiconductor photocatalysis.

    Kim, Jae-Hyuk; Kim, Jae-Hong


    We herein report the first instance of aqueous-phase photosensitization of semiconductor photocatalysts (WO(3) loaded with Pt) through triplet-triplet annihilation (TTA)-based upconversion of sub-band-gap photons. The TTA-based upconversion (UC) was achieved in the aqueous phase by encapsulating the solvent phase containing a benchmark platinum(II) octaethylporphyrin/9,10-diphenylanthracene sensitizer/acceptor pair in a rigid polymer shell in the form of aqueous dispersible microcapsules. A mixture of hexadecane and polyisobutylene was used as the inner solvent phase. This eliminated the need for the deoxygenation step that is essential for existing TTA-based UC processes and enabled stable UC to occur even after a month of exposure to the ambient environment. The photoluminescence properties were examined, and UC-assisted photochemical production of hydroxyl radical from green (532 nm) light irradiation was demonstrated for the first time.

  16. Atomic Layer Deposited Thin Films for Dielectrics, Semiconductor Passivation, and Solid Oxide Fuel Cells

    Xu, Runshen

    Atomic layer deposition (ALD) utilizes sequential precursor gas pulses to deposit one monolayer or sub-monolayer of material per cycle based on its self-limiting surface reaction, which offers advantages, such as precise thickness control, thickness uniformity, and conformality. ALD is a powerful means of fabricating nanoscale features in future nanoelectronics, such as contemporary sub-45 nm metal-oxide-semiconductor field effect transistors, photovoltaic cells, near- and far-infrared detectors, and intermediate temperature solid oxide fuel cells. High dielectric constant, kappa, materials have been recognized to be promising candidates to replace traditional SiO2 and SiON, because they enable good scalability of sub-45 nm MOSFET (metal-oxide-semiconductor field-effect transistor) without inducing additional power consumption and heat dissipation. In addition to high dielectric constant, high-kappa materials must meet a number of other requirements, such as low leakage current, high mobility, good thermal and structure stability with Si to withstand high-temperature source-drain activation annealing. In this thesis, atomic layer deposited Er2O3 doped TiO2 is studied and proposed as a thermally stable amorphous high-kappa dielectric on Si substrate. The stabilization of TiO2 in its amorphous state is found to achieve a high permittivity of 36, a hysteresis voltage of less than 10 mV, and a low leakage current density of 10-8 A/cm-2 at -1 MV/cm. In III-V semiconductors, issues including unsatisfied dangling bonds and native oxides often result in inferior surface quality that yields non-negligible leakage currents and degrades the long-term performance of devices. The traditional means for passivating the surface of III-V semiconductors are based on the use of sulfide solutions; however, that only offers good protection against oxidation for a short-term (i.e., one day). In this work, in order to improve the chemical passivation efficacy of III-V semiconductors

  17. Solid lipid nanoparticles for encapsulation of hydrophilic drugs by an organic solvent free double emulsion technique.

    Becker Peres, Luana; Becker Peres, Laize; de Araújo, Pedro Henrique Hermes; Sayer, Claudia


    Encapsulation of hydrophilic compounds for drug delivery systems with high loading efficiency is not easily feasible and remains a challenge, mainly due to the leaking of the drug to the outer aqueous phase during nanoparticle production. Usually, encapsulation of hydrophilic drugs is achieved by using double emulsion or inverse miniemulsion systems that often require the use of organic solvents, which may generate toxicological issues arising from solvent residues. Herein, we present the preparation of solid lipid nanoparticles loaded with a hydrophilic compound by a novel organic solvent free double emulsion/melt dispersion technique. The main objective of this study was to investigate the influence of important process and formulation variables, such as lipid composition, surfactant type, sonication parameters and lipid solidification conditions over physicochemical characteristics of SLN dispersion. Particle size and dispersity, as well as dispersion stability were used as responses. SLN dispersions with average size ranging from 277 to 550 nm were obtained, showing stability for over 60 days at 4 °C depending on the chosen emulsifying system. Entrapment efficiency of fluorescent dyes used as model markers was assessed by fluorescence microscopy and UV-vis spectrophotometry and results suggest that the obtained lipid based nanoparticles could be potentially applied as a delivery system of water soluble drugs.

  18. Some Chemical and Electronic Considerations of Solid State Semiconductor Crystals.

    Hinitz, Herman J.


    Describes the trend toward the use of electronic instrumentation to monitor and measure various parameters in chemical reactions. Stresses that a knowledge of the operational relationships involved in such instruments is essential for students beginning in science. Discusses electrostatic charges, semiconductor crystals, electronic conductors,…

  19. Solid-state lighting : lamp targets and implications for the semiconductor chip.

    Tsao, Jeffrey Yeenien


    A quiet revolution is underway. Over the next 5-10 years inorganic-semiconductor-based solid-state lighting technology is expected to outperform first incandescent, and then fluorescent and high-intensity-discharge, lighting. Along the way, many decision points and technical challenges will be faced. To help understand these challenges, the U.S. Department of Energy, the Optoelectronics Industry Development Association and the National Electrical Manufacturers Association recently updated the U.S. Solid-State Lighting Roadmap. In the first half of this paper, we present an overview of the high-level targets of the inorganic-semiconductor part of that update. In the second half of this paper, we discuss some implications of those high-level targets on the GaN-based semiconductor chips that will be the 'engine' for solid-state lighting.

  20. Encapsulation of fish oil into hollow solid lipid micro- and nanoparticles using carbon dioxide.

    Yang, Junsi; Ciftci, Ozan Nazim


    Fish oil was encapsulated in hollow solid lipid micro- and nanoparticles formed from fully hydrogenated soybean oil (FHSO) using a novel green method based on atomization of supercritical carbon dioxide (SC-CO2)-expanded lipid. The highest fish oil loading efficiency (97.5%, w/w) was achieved at 50%, w/w, initial fish oil concentration. All particles were spherical and in the dry free-flowing form; however, less smooth surface with wrinkles was observed when the initial fish oil concentration was increased up to 50%. With increasing initial fish oil concentration, melting point of the fish oil-loaded particles shifted to lower onset melting temperatures, and major polymorphic form transformed from α to β and/or β'. Oxidative stability of the loaded fish oil was significantly increased compared to the free fish oil (poil formulation, which makes the handling and storage feasible and convenient. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. III-V semiconductor solid solution single crystal growth

    Gertner, E. R.


    The feasibility and desirability of space growth of bulk IR semiconductor crystals for use as substrates for epitaxial IR detector material were researched. A III-V ternary compound (GaInSb) and a II-VI binary compound were considered. Vapor epitaxy and quaternary epitaxy techniques were found to be sufficient to permit the use of ground based binary III-V crystals for all major device applications. Float zoning of CdTe was found to be a potentially successful approach to obtaining high quality substrate material, but further experiments were required.

  2. Solid state technology: A compilation. [on semiconductor devices


    A compilation, covering selected solid state devices developed and integrated into systems by NASA to improve performance, is presented. Data are also given on device shielding in hostile radiation environments.

  3. Development of design, qualification, screening, and application requirements for plastic encapsulated solid-state devices for space applications


    Test data were collected on 1035 plastic encapsulated devices and 75 hermetically scaled control group devices that were purchased from each of five different manufacturers in the categories of (1) low power Schottsky TTL (bipolar) digital circuits; (2) CMOS digital circuits; (3) operational amplifier linear circuits; and (4) NPN transistors. These parts were subjected to three different initial screening conditions, then to extended life testing, to determine any possible advantages or trends for any particular screen. Several tests were carried out in the areas of flammability testing, humidity testing, high pressure steam (auroclave) testing, and high temperature storage testing. Test results are presented. Procurement and application considerations for use of plastic encapsulated semiconductors are presented and a statistical analysis program written to study the log normal distributions resulting from life testing is concluded.

  4. α-Tocopherol succinate improves encapsulation and anticancer activity of doxorubicin loaded in solid lipid nanoparticles.

    Oliveira, Mariana S; Mussi, Samuel V; Gomes, Dawidson A; Yoshida, Maria Irene; Frezard, Frederic; Carregal, Virgínia M; Ferreira, Lucas A M


    This work aimed to develop solid lipid nanoparticles (SLN) co-loaded with doxorubicin and α-tocopheryl succinate (TS), a succinic acid ester of α-tocopherol that exhibits anticancer actions, evaluating the influence of TS on drug encapsulation efficiency. The SLN were characterized for size, zeta potential, entrapment efficiency (EE), and drug release. Studies of in vitro anticancer activity were also conducted. The EE was significantly improved from 30 ± 1% to 96 ± 2% for SLN without and with TS at 0.4%, respectively. In contrast, a reduction in particle size from 298 ± 1 to 79 ± 1 nm was observed for SLN without and with TS respectively. The doxorubicin release data show that SLN provide a controlled drug release. The in vitro studies showed higher cytotoxicity for doxorubicin-TS-loaded SLN than for free doxorubicin in breast cancer cells. These findings suggest that TS-doxorubicin-loaded SLN is a promising alternative for the treatment of cancer.

  5. Facile fabrication of reduced graphene oxide-encapsulated silica: a sorbent for solid-phase extraction.

    Luo, Yan-Bo; Zhu, Gang-Tian; Li, Xiao-Shui; Yuan, Bi-Feng; Feng, Yu-Qi


    In this study, a facile hydrothermal reduction strategy was developed for the preparation of reduced graphene oxide-encapsulated silica (SiO2@rGO). Compared with other conventional methods for the synthesis of SiO2@rGO, the proposed strategy endowed the obtained SiO2@rGO with larger amount of immobilized rGO. The prepared functionalized silica shows remarkable adsorption capacity toward chlorophenols (CPs) and peptides. When it was used as solid-phase extraction (SPE) sorbent, a superior recovery could be obtained compared to commercial sorbents, such as C18 silica, graphitized carbon black and carbon nanotubes. Based on these, the prepared material was used as SPE sorbent for the enrichment of CPs, and a method for the analysis of CPs in water samples was established by coupling SPE with high performance liquid chromatography-ultra violet detection (SPE-HPLC/UV). In addition, the obtained SiO2@rGO was further successfully extended to the enrichment of peptides in bovine serum albumin (BSA) digests.

  6. Conductors, semiconductors, superconductors an introduction to solid state physics

    Huebener, Rudolf P


    This undergraduate textbook provides an introduction to the fundamentals of solid state physics, including a description of the key people in the field and the historic context. The book concentrates on the electric and magnetic properties of materials. It is written for students up to the bachelor level in the fields of physics, materials science, and electric engineering. Because of its vivid explanations and its didactic approach, it can also serve as a motivating pre-stage and supporting companion in the study of the established and more detailed textbooks of solid state physics. The textbook is suitable for a quick repetition prior to examinations. This second edition is extended considerably by detailed mathematical treatments in many chapters, as well as extensive coverage of magnetic impurities.

  7. Conductors, semiconductors, superconductors an introduction to solid state physics

    Huebener, Rudolf P


    In the second half of the last century solid state physics and materials science experienced a great advance and established itself as an important and independent new field. This book provides an introduction to the fundamentals of solid state physics, including a description of the key people in the field and the historic context. The book concentrates on the electric and magnetic properties of materials. It is written for students up to the bachelor in the fields of physics, materials science, and electric engineering. Because of its vivid explanations and its didactic approach, it can also serve as a motivating pre-stage and supporting companion in the study of the established and more detailed textbooks of solid state physics. The book is suitable for a quick repetition prior to examinations. For his scientific accomplishments, in 1992 the author received the Max-Planck Research Price and in 2001 the Cryogenics Price. He studied physics and mathematics at the University of Marburg, as well at the Technic...

  8. Characterization and evaluation of sensory acceptability of ice creams incorporated with beta-carotene encapsulated in solid lipid microparticles

    Juliana Gobbi de LIMA

    Full Text Available Abstract The feasibility of incorporating beta-carotene-loaded solid lipid microparticles (BCSLM into vanilla ice creams was investigated, through the physico-chemical characterization and evaluation of sensory acceptability of the products products. The BCSLM were produced with palm stearin as the lipid phase, hydrolyzed soy protein isolate as the surfactant, and xanthan gum as the thickener. The results showed similar values of proximate composition, total soluble solids, pH, and overrun for all formulations. On the other hand, colorimetric evaluations showed that the ice cream produced with partial substitution of artificial additives by BCSLM containing alpha-tocopherol presented a more intense color, while in the product with non-encapsulated beta-carotene, a fast degradation of carotenoid was confirmed, highlighting the importance of the encapsulation techniques. The results of the sensorial analysis of the products were highly satisfactory and showed that the panelists preferred the ice creams produced with BCSLM containing alpha-tocopherol and with partial substitution of artificial additives by BCSLM containing alpha-tocopherol, confirming the feasibility of incorporating BCSLM into ice creams to reduce the application of artificial dyes to the product.

  9. Novel Solid Encapsulation of Ethylene Gas Using Amorphous α-Cyclodextrin and the Release Characteristics.

    Ho, Binh T; Bhandari, Bhesh R


    This research investigated the encapsulation of ethylene gas into amorphous α-cyclodextrins (α-CDs) at low (LM) and high (HM) moisture contents at 1.0-1.5 MPa for 24-120 h and its controlled release characteristics at 11.2-52.9% relative humidity (RH) for 1-168 h. The inclusion complexes (ICs) were characterized using X-ray diffractometry (XRD), nuclear magnetic resonance spectroscopy (CP-MAS (13)C NMR), and scanning electron microscopy (SEM). Ethylene concentrations in the ICs were from 0.45 to 0.87 mol of ethylene/mol CD and from 0.42 to 0.54 mol of ethylene/mol CD for LM and HM α-CDs, respectively. Ethylene gas released from the encapsulated powder at higher rates with increasing RH. An analysis of release kinetics using Avrami's equation showed that the LM and HM amorphous α-CDs were not associated with significant differences in release constant k and parameter n for any given RH condition. NMR spectra showed the presence of the characteristic carbon-carbon double bond of ethylene gas in the encapsulated α-CD powder.

  10. A new polarimeter scheme based on solid state semiconductors Un nuevo esquema para polarímetros basado en semiconductor de estado sólido

    Heiner Castro Gutierrez


    A new kind of polarimeter scheme is suggested using solid state semiconductors. The new approach is based on the modulation over the intensities of the diffracted beams through a two-dimensional chiral grating, reported recently. It will be demonstrated that at least four intensity measurements of no equivalent diffracted beams are needed in order to estimate the polarization state of the incident beam. The incident beam azimuth was varied by routing a linear polarizer lens mounting in a step...

  11. Gigahertz dual-comb modelocked diode-pumped semiconductor and solid-state lasers

    Link, S. M.; Mangold, M.; Golling, M.; Klenner, A.; Keller, U.


    We present a simple approach to generate simultaneously two gigahertz mode-locked pulse trains from a single gain element. A bi-refringent crystal in the laser cavity splits the one cavity beam into two cross-polarized and spatially separated beams. This polarization-duplexing is successfully demonstrated for both a semiconductor disk laser (i.e. MIXSEL) and a diode-pumped solid-state Nd:YAG laser. The beat between the two beams results in a microwave frequency comb, which represents a direct link between the terahertz optical frequencies and the electronically accessible microwave regime. This dual-output technique enables compact and cost-efficient dual-comb lasers for spectroscopy applications.

  12. Solid-state semiconductor optical cryocooler based on CdS nanobelts.

    Li, Dehui; Zhang, Jun; Wang, Xinjiang; Huang, Baoling; Xiong, Qihua


    We demonstrate the laser cooling of silicon-on-insulator (SOI) substrate using CdS nanobelts. The local temperature change of the SOI substrate exactly beneath the CdS nanobelts is deduced from the ratio of the Stokes and anti-Stokes Raman intensities from the Si layer on the top of the SOI substrate. We have achieved a 30 and 20 K net cooling starting from 290 K under a 3.8 mW 514 nm and a 4.4 mW 532 nm pumping, respectively. In contrast, a laser heating effect has been observed pumped by 502 and 488 nm lasers. Theoretical analysis based on the general static heat conduction module in the Ansys program package is conducted, which agrees well with the experimental results. Our investigations demonstrate the laser cooling capability of an external thermal load, suggesting the applications of II-VI semiconductors in all-solid-state optical cryocoolers.

  13. Polymer-encapsulated carbon capture liquids that tolerate precipitation of solids for increased capacity

    Aines, Roger D; Bourcier, William L; Spadaccini, Christopher M; Stolaroff, Joshuah K


    A system for carbon dioxide capture from flue gas and other industrial gas sources utilizes microcapsules with very thin polymer shells. The contents of the microcapsules can be liquids or mixtures of liquids and solids. The microcapsules are exposed to the flue gas and other industrial gas and take up carbon dioxide from the flue gas and other industrial gas and eventual precipitate solids in the capsule.

  14. Co-Encapsulation of Doxorubicin With Galactoxyloglucan Nanoparticles for Intracellular Tumor-Targeted Delivery in Murine Ascites and Solid Tumors

    Manu M. Joseph


    Full Text Available Doxorubicin (Dox treatment is limited by severe toxicity and frequent episodes of treatment failure. To minimize adverse events and improve drug delivery efficiently and specifically in cancer cells, encapsulation of Dox with naturally obtained galactoxyloglucan polysaccharide (PST001, isolated from Tamarindus indica was attempted. Thus formed PST-Dox nanoparticles induced apoptosis and exhibited significant cytotoxicity in murine ascites cell lines, Dalton’s lymphoma ascites and Ehrlich’s ascites carcinoma. The mechanism contributing to the augmented cytotoxicity of nanoconjugates at lower doses was validated by measuring the Dox intracellular uptake in human colon, leukemic and breast cancer cell lines. PST-Dox nanoparticles showed rapid internalization of Dox into cancer cells within a short period of incubation. Further, in vivo efficacy was tested in comparison to the parent counterparts - PST001 and Dox, in ascites and solid tumor syngraft mice models. Treatment of ascites tumors with PST-Dox nanoparticles significantly reduced the tumor volume, viable tumor cell count, and increased survival and percentage life span in the early, established and prophylactic phases of the disease. Administration of nanoparticles through intratumoral route delivered more robust antitumor response than the intraperitoneal route in solid malignancies. Thus, the results indicate that PST-Dox nanoparticles have greater potential compared to the Dox as targeted drug delivery nanocarriers for loco regional cancer chemotherapy applications.

  15. Improved performance of high average power semiconductor arrays for applications in diode pumped solid state lasers

    Beach, R.; Emanuel, M.; Benett, W.; Freitas, B.; Ciarlo, D.; Carlson, N.; Sutton, S.; Skidmore, J.; Solarz, R.


    The average power performance capability of semiconductor diode laser arrays has improved dramatically over the past several years. These performance improvements, combined with cost reductions pursued by LLNL and others in the fabrication and packaging of diode lasers, have continued to reduce the price per average watt of laser diode radiation. Presently, we are at the point where the manufacturers of commercial high average power solid state laser systems used in material processing applications can now seriously consider the replacement of their flashlamp pumps with laser diode pump sources. Additionally, a low cost technique developed and demonstrated at LLNL for optically conditioning the output radiation of diode laser arrays has enabled a new and scalable average power diode-end-pumping architecture that can be simply implemented in diode pumped solid state laser systems (DPSSL`s). This development allows the high average power DPSSL designer to look beyond the Nd ion for the first time. Along with high average power DPSSL`s which are appropriate for material processing applications, low and intermediate average power DPSSL`s are now realizable at low enough costs to be attractive for use in many medical, electronic, and lithographic applications.

  16. Thin film solid-state reactions forming carbides as contact materials for carbon-containing semiconductors

    Leroy, W. P.; Detavernier, C.; Van Meirhaeghe, R. L.; Lavoie, C.


    Metal carbides are good candidates to contact carbon-based semiconductors (SiC, diamond, and carbon nanotubes). Here, we report on an in situ study of carbide formation during the solid-state reaction between thin films. The solid-state reaction was examined between 11 transition metals (W, Mo, Fe, Cr, V, Nb, Mn, Ti, Ta, Zr, and Hf) and an amorphous carbon layer. Capping layers (C or TiN) of different thicknesses were applied to prevent oxidation. Carbide formation is evidenced for nine metals and the phases formed have been identified (for a temperature ranging from 100to1100°C). W first forms W2C and then WC; Mo forms Mo2C; Fe forms Fe3C; Cr first forms metastable phases Cr2C and Cr3C2-x, and finally forms Cr3C2; V forms VCx; Nb transforms into Nb2C followed by NbC; Ti forms TiC; Ta first forms Ta2C and then TaC; and Hf transforms into HfC. The activation energy for the formation of the various carbide phases has been obtained by in situ x-ray diffraction.

  17. Effects of Formulation Variables on the Particle Size and Drug Encapsulation of Imatinib-Loaded Solid Lipid Nanoparticles.

    Gupta, Biki; Poudel, Bijay Kumar; Pathak, Shiva; Tak, Jin Wook; Lee, Hee Hyun; Jeong, Jee-Heon; Choi, Han-Gon; Yong, Chul Soon; Kim, Jong Oh


    Imatinib (IMT), an anticancer agent, inhibits receptor tyrosine kinases and is characterized by poor aqueous solubility, extensive first-pass metabolism, and rapid clearance. The aims of the current study are to prepare imatinib-loaded solid lipid nanoparticles (IMT-SLN) and study the effects of associated formulation variables on particle size and drug encapsulation on IMT-SLN using an experimental design. IMT-SLN was optimized by use of a "combo" approach involving Plackett-Burman design (PBD) and Box-Behnken design (BBD). PBD screening resulted in the determination of organic-to-aqueous phase ratio (O/A), drug-to-lipid ratio (D/L), and amount of Tween® 20 (Tw20) as three significant variables for particle size (S z), drug loading (DL), and encapsulation efficiency (EE) of IMT-SLN, which were used for optimization by BBD, yielding an optimized criteria of O/A = 0.04, D/L = 0.03, and Tw20 = 2.50% w/v. The optimized IMT-SLN exhibited monodispersed particles with a size range of 69.0 ± 0.9 nm, ζ-potential of -24.2 ± 1.2 mV, and DL and EE of 2.9 ± 0.1 and 97.6 ± 0.1% w/w, respectively. Results of in vitro release study showed a sustained release pattern, presumably by diffusion and erosion, with a higher release rate at pH 5.0, compared to pH 7.4. In conclusion, use of the combo experimental design approach enabled clear understanding of the effects of various formulation variables on IMT-SLN and aided in the preparation of a system which exhibited desirable physicochemical and release characteristics.

  18. Effect of Solid Lipid Nanoparticle-Encapsulated Antimicrobial Peptide on Keratinocyte Migration and Wound Healing


    suspension with100-µL trypan blue (1:1) (Sigma-Aldrich, St. Louis, MO). 10 µL of cell and trypan blue solution was analyzed by Countess TM...of morphine and solid lipid nanoparticle. Journal of Biotechnology 2010 148: 24-30. 24. Marsh PD. Dental Plaque: biological significance of a...nanoparticles (SLN) and nanostructured lipid carriers (NLC) in cosmetic and dermatological preparations. Adv Drug Deliv. 2002 Rev 54 supplement 1: S131-55

  19. Flow-Solution-Liquid-Solid Growth of Semiconductor Nanowires: A Novel Approach for Controlled Synthesis

    Hollingsworth, Jennifer A. [Los Alamos National Laboratory; Palaniappan, Kumaranand [Los Alamos National Laboratory; Laocharoensuk, Rawiwan [National Science and Technology Center, Thailand; Smith, Nickolaus A. [Los Alamos National Laboratory; Dickerson, Robert M. [Los Alamos National Laboratory; Casson, Joanna L. [Los Alamos National Laboratory; Baldwin, Jon K. [Los Alamos National Laboratory


    Semiconductor nanowires (SC-NWs) have potential applications in diverse technologies from nanoelectronics and photonics to energy harvesting and storage due to their quantum-confined opto-electronic properties coupled with their highly anisotropic shape. Here, we explore new approaches to an important solution-based growth method known as solution-liquid-solid (SLS) growth. In SLS, molecular precursors are reacted in the presence of low-melting metal nanoparticles that serve as molten fluxes to catalyze the growth of the SC-NWs. The mechanism of growth is assumed to be similar to that of vapor-liquid-solid (VLS) growth, with the clear distinctions of being conducted in solution in the presence of coordinating ligands and at relatively lower temperatures (<300 C). The resultant SC-NWs are soluble in common organic solvents and solution processable, offering advantages such as simplified processing, scale-up, ultra-small diameters for quantum-confinement effects, and flexible choice of materials from group III-V to groups II-VI, IV-VI, as well as truly ternary I-III-VI semiconductors as we recently demonstrates. Despite these advantages of SLS growth, VLS offers several clear opportunities not allowed by conventional SLS. Namely, VLS allows sequential addition of precursors for facile synthesis of complex axial heterostructures. In addition, growth proceeds relatively slowly compared to SLS, allowing clear assessments of growth kinetics. In order to retain the materials and processing flexibility afforded by SLS, but add the elements of controlled growth afforded by VLS, we transformed SLS into a flow based method by adapting it to synthesis in a microfluidic system. By this new method - so-called 'flow-SLS' (FSLS) - we have now demonstrated unprecedented fabrication of multi-segmented SC-NWs, e.g., 8-segmented CdSe/ZnSe defined by either compositionally abrupt or alloyed interfaces as a function of growth conditions. In addition, we have studied growth

  20. Design and optimization of micro-semiconductor bridge used for solid propellant microthrusters array

    Ru, Chengbo; Dai, Ji; Xu, Jianbing; Ye, Yinghua; Zhu, Peng; Shen, Ruiqi


    Igniter is the basic component of MEMS-based solid propellant microthrusters (SPM) array, which should response fast with low dissipated energy. To satisfy the requirements, micro-semiconductor bridge (MSCB) with dual V-angles contributing to the reduction of dissipated energy is introduced into the array. The electrical explosion characteristics of MSCB investigated under constant voltage, in the considerations of the limit of power supply in the micro/nanosatellite, are similar to those under capacitive discharge. The bridge was completely vaporized and burst into the hot plasma under high-level voltage. While under low-level voltage, the bridge was partly vaporized without detected plasma. The 3#SCB (90° V-angle) with the smallest power density resulting in the lowest applied voltage (12.0 V) and the 2#SCB with the smallest narrow width (Wmin) leading to the lowest average power (11.3 W) were chosen to the further optimization. The ignition tests were implemented to examine the ignition reliability of the contractible igniters, which were optimized to satisfy the voltage limitation with sufficient ignition capacity. The results show that the effective SCB with lowest dissipated power is the 3#-3SCB, which function within 100 μ under 7.0 V, and the average power below 5.0 W.

  1. All-solid-state repetitive semiconductor opening switch-based short pulse generator.

    Ding, Zhenjie; Hao, Qingsong; Hu, Long; Su, Jiancang; Liu, Guozhi


    The operating characteristics of a semiconductor opening switch (SOS) are determined by its pumping circuit parameters. SOS is still able to cut off the current when pumping current duration falls to the order of tens of nanoseconds and a short pulse forms simultaneously in the output load. An all-solid-state repetitive SOS-based short pulse generator (SPG100) with a three-level magnetic pulse compression unit was successfully constructed. The generator adopts magnetic pulse compression unit with metallic glass and ferrite cores, which compresses a 600 V, 10 mus primary pulse into short pulse with forward pumping current of 825 A, 60 ns and reverse pumping current of 1.3 kA, 30 ns. The current is sent to SOS in which the reverse pumping current is interrupted. The generator is capable of providing a pulse with the voltage of 120 kV and duration of 5-6 ns while output load being 125 Omega. The highest repetition rate is up to 1 kHz.

  2. Graphene-encapsulated silica as matrix solid-phase dispersion extraction sorbents for the analysis of poly-methoxylated flavonoids in the leaves of Murraya panaculata (L.) Jack.

    Sun, Ting; Li, Xuwen; Yang, Jie; Li, Lanjie; Jin, Yongri; Shi, Xiaolei


    In this study, graphene-encapsulated silica was synthesized by a hydrothermal reduction strategy. The presence of silica in graphene was identified by Fourier-transform infrared spectrometry, X-ray diffraction and scanning electron microscopy. The graphene-encapsulated silica subsequently was used as adsorbent for matrix solid-phase dispersion extraction of poly-methoxylated flavonoids from the dried leaves of Murraya panaculata (L.) Jack. Compared with the other adsorbents (graphene, silica gel, C18 silica, neutral alumina, diatomaceous earth) and without any adsorbents, better results were obtained. Then a method for analysis of poly-methoxylated flavonoids was established by coupling matrix solid-phase dispersion extraction with ultra high performance liquid chromatography and UV detection. Compared with reflux extraction and ultrasonic extraction, the proposed method is quicker, more efficient and more environmental protection. Less than 10 min is needed from extraction to detection.

  3. Ion pairing with linoleic acid simultaneously enhances encapsulation efficiency and antibacterial activity of vancomycin in solid lipid nanoparticles.

    Kalhapure, Rahul S; Mocktar, Chunderika; Sikwal, Dhiraj R; Sonawane, Sandeep J; Kathiravan, Muthu K; Skelton, Adam; Govender, Thirumala


    Ion pairing of a fatty acid with an antibiotic may be an effective strategy for formulation optimization of a nanoantibiotic system. The aim of this study was therefore to explore the potential of linoleic acid (LA) as an ion pairing agent to simultaneously enhance encapsulation efficiency and antibacterial activity of triethylamine neutralized vancomycin (VCM) in solid lipid nanoparticles (SLNs). The prepared VCM-LA2 conjugate was characterized by Fourier transform-infrared (FT-IR) spectroscopy, logP and binding energy calculations. The shifts in the FT-IR frequencies of COOH, NH2 and CO functionalities, an increase in logP value (1.37) and a lower interaction energy between LA and VCM (-125.54 kcal/mol) confirmed the formation of the conjugate. SLNs were prepared by a hot homogenization and ultrasonication method, and characterized for size, polydispersity index (PI), zeta potential (ZP), entrapment efficiency (%EE), surface morphology and physical stability. In vitro antibacterial activity studies against Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) were conducted. Size, PI and ZP for VCM-LA2_SLNs were 102.7±1.01, 0.225±0.02 and -38.8±2.1 (mV) respectively. SLNs were also stable at 4 °C for 3 months. %EE for VCM-HCl_SLNs and VCM-LA2_SLNs were 16.81±3.64 and 70.73±5.96 respectively, indicating a significant improvement in encapsulation of the drug through ion pairing with LA. Transmission electron microscopy images showed spherical nanoparticles with sizes in the range of 95-100 nm. After 36 h, VCM-HCl showed no activity against MRSA. However, the minimum inhibitory concentration for VCM-HCl_SLNs and VCM-LA2_SLNs were 250 and 31.25 μg/ml respectively against S. aureus, while against MRSA it was 500 and 15.62 μg/ml respectively. This confirms the enhanced antibacterial activity of VCM-LA2_SLNs over VCM-HCl_SLNs. These findings therefore suggest that VCM-LA2_SLNs is a promising nanoantibiotic system for effective treatment against both

  4. Influence of encapsulated functional lipids on crystal structure and chemical stability in solid lipid nanoparticles: Towards bioactive-based design of delivery systems.

    Salminen, Hanna; Gömmel, Christina; Leuenberger, Bruno H; Weiss, Jochen


    We investigated the influence of physicochemical properties of encapsulated functional lipids--vitamin A, β-carotene and ω-3 fish oil--on the structural arrangement of solid lipid nanoparticles (SLN). The relationship between the crystal structure and chemical stability of the incorporated bioactive lipids was evaluated with different emulsifier compositions of a saponin-rich, food-grade Quillaja extract alone or combined with high-melting or low-melting lecithins. The major factors influencing the structural arrangement and chemical stability of functional lipids in solid lipid dispersions were their solubility in the aqueous phase and their crystallization temperature in relation to that of the carrier lipid. The results showed that the stabilization of the α-subcell crystals in the lattice of the carrier lipid is a key parameter for forming stable solid lipid dispersions. This study contributes to a better understanding of SLN as a function of the bioactive lipid. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Characterization Methods of Encapsulates

    Zhang, Zhibing; Law, Daniel; Lian, Guoping

    Food active ingredients can be encapsulated by different processes, including spray drying, spray cooling, spray chilling, spinning disc and centrifugal co-extrusion, extrusion, fluidized bed coating and coacervation (see Chap. 2 of this book). The purpose of encapsulation is often to stabilize an active ingredient, control its release rate and/or convert a liquid formulation into a solid which is easier to handle. A range of edible materials can be used as shell materials of encapsulates, including polysaccharides, fats, waxes and proteins (see Chap. 3 of this book). Encapsulates for typical industrial applications can vary from several microns to several millimetres in diameter although there is an increasing interest in preparing nano-encapsulates. Encapsulates are basically particles with a core-shell structure, but some of them can have a more complex structure, e.g. in a form of multiple cores embedded in a matrix. Particles have physical, mechanical and structural properties, including particle size, size distribution, morphology, surface charge, wall thickness, mechanical strength, glass transition temperature, degree of crystallinity, flowability and permeability. Information about the properties of encapsulates is very important to understanding their behaviours in different environments, including their manufacturing processes and end-user applications. E.g. encapsulates for most industrial applications should have desirable mechanical strength, which should be strong enough to withstand various mechanical forces generated in manufacturing processes, such as mixing, pumping, extrusion, etc., and may be required to be weak enough in order to release the encapsulated active ingredients by mechanical forces at their end-user applications, such as release rate of flavour by chewing. The mechanical strength of encapsulates and release rate of their food actives are related to their size, morphology, wall thickness, chemical composition, structure etc. Hence

  6. Controlled growth of semiconductor crystals

    Bourret-Courchesne, Edith D.


    A method for growth of III-V, II-VI and related semiconductor single crystals that suppresses random nucleation and sticking of the semiconductor melt at the crucible walls. Small pieces of an oxide of boron B.sub.x O.sub.y are dispersed throughout the comminuted solid semiconductor charge in the crucible, with the oxide of boron preferably having water content of at least 600 ppm. The crucible temperature is first raised to a temperature greater than the melt temperature T.sub.m1 of the oxide of boron (T.sub.m1 K. for boron oxide B.sub.2 O.sub.3), and the oxide of boron is allowed to melt and form a reasonably uniform liquid layer between the crucible walls and bottom surfaces and the still-solid semiconductor charge. The temperature is then raised to approximately the melt temperature T.sub.m2 of the semiconductor charge material, and crystal growth proceeds by a liquid encapsulated, vertical gradient freeze process. About half of the crystals grown have a dislocation density of less than 1000/cm.sup.2. If the oxide of boron has water content less than 600 ppm, the crucible material should include boron nitride, a layer of the inner surface of the crucible should be oxidized before the oxide of boron in the crucible charge is melted, and the sum of thicknesses of the solid boron oxide layer and liquid boron oxide layer should be at least 50 .mu.m.

  7. Semiconductor/Solid Electrolyte Junctions for Optical Information Storage. Electrochromic Effects on Heptylviologen Incorporated within a Solid Polymer Electrolyte Cell.


    cathode5 . Electrochromic devices based upon these electrochemically reversible viologen redox couples would greatly benefit by their incorporation...electrolyte analogs. Here we wish to discuss some recent work from our laboratory on solid- state electrochromic cells in which heptyl viologen (HV2+) was...OPTICAL INFORMATION STORAGE. ELECTROCHROMIC EFFECTS QN HEPTYLVIOLOGEN INCORPORATED WITHIN A SOLID POLYMER ELECTROLYTE CELL By Anthony F. Sammells and

  8. Encapsulation and retention of chelated-copper inside hydrophobic nanoparticles: Liquid cored nanoparticles show better retention than a solid core formulation.

    Hervella, Pablo; Parra, Elisa; Needham, David


    In the field of imaging, (18)F-fluorodeoxyglucose (FDG) PET imaging allows evaluation of glucose metabolism and is the most widely used imaging agent clinically for metastatic cancer. While it can certainly detect the metastatic disease, in order to provide a more fully "individualized medicine" strategy of detection and pharmaceutical treatment, what is needed are additional imaging nanoparticles that resemble the subsequently-administered nanoparticle drug delivery system itself. Both of these nanoparticles must also be able to take advantage of what may well be a limited EPR effect in human tumors, which in and of itself still needs to be characterized in the clinic. Administration of FDG, followed by a nanoparticle imaging agent, followed by a therapeutic nanoparticle would constitute such an "individualized medicine strategy", especially for anti-metastasis approaches. It is here that our endogenous-inspired nanoparticle strategies for imaging and therapeutics are focused on encapsulating and retaining imaging ions such as copper inside novel hydrophobic nanoparticles. In this paper, we describe a new approach to label the core of hydrophobic nanoparticles composed of Glyceryl Trioleate (Triolein) with copper using the hydrophobic chelator Octaethyl porphyrin (OEP). The research plan for this study was to (1) Formulate nanoparticles and control nanoparticle size using a modification of the solvent injection technique, named fast ethanol injection; (2) Chelate copper into the octaethyl porphyrin; (3) Encapsulate OEP-Cu in nanoparticles: the encapsulation efficiency of copper into liquid nanoparticles (LNP), solid nanoparticles (SNP) and phospholipid liposomes (PL) was evaluated by UV-Vis and atomic absorption spectroscopy; (4) Retain the encapsulated OEP-Cu in the liquid or solid cores of the nanoparticles in the presence of a lipid sink. (1) The size of the nanoparticles was found to be strongly dependent on the Reynolds number and the initial concentration of

  9. Interaction of CdSe/ZnS core-shell semiconductor nanocrystals in solid thin films

    Chistyakov, A. A.; Martynov, I. L.; Mochalov, K. E.; Oleinikov, V. A.; Sizova, S. V.; Ustinovich, E. A.; Zakharchenko, K. V.


    The optical properties of CdSe/ZnS semiconductor nanocrystals with the core-shell structure are studied upon visible-laser excitation in a wide range of flux densities. It is demonstrated that the dimensional quantization effect is preserved in the films with a limiting high concentration of nanocry

  10. Development of Solid-State Electrochemiluminescence (ECL Sensor Based on Ru(bpy32+-Encapsulated Silica Nanoparticles for the Detection of Biogenic Polyamines

    Anna-Maria Spehar-Délèze


    Full Text Available A solid state electrochemiluminescence (ECL sensor based on Ru(bpy32+-encapsulated silica nanoparticles (RuNP covalently immobilised on a screen printed carbon electrode has been developed and characterised. RuNPs were synthesised using water-in-oil microemulsion method, amino groups were introduced on their surface, and they were characterised by transmission electron microscopy. Aminated RuNPs were covalently immobilised on activate screen-printed carbon electrodes to form a solid state ECL biosensor. The biosensor surfaces were characterised using electrochemistry and scanning electron microscopy, which showed that aminated nanoparticles formed dense 3D layers on the electrode surface thus allowing immobilisation of high amount of Ru(bpy32+. The developed sensor was used for ECL detection of biogenic polyamines, namely spermine, spermidine, cadaverine and putrescine. The sensor exhibited high sensitivity and stability.

  11. Solid-state reactions to synthesize nanostructured lead selenide semiconductor powders by high-energy milling

    Rojas-Chavez, H., E-mail: [Centro de Investigacion e Innovacion Tecnologica - IPN, Cerrada de CECATI s/n, Col. Santa Catarina, Del. Azcapotzalco (Mexico) and Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada - IPN, Legaria 694, Col. Irrigacion, Del. Miguel Hidalgo (Mexico); Reyes-Carmona, F. [Facultad de Quimica - UNAM, Circuito de la Investigacion Cientifica s/n, C.U. Del. Coyoacan (Mexico); Jaramillo-Vigueras, D. [Centro de Investigacion e Innovacion Tecnologica - IPN, Cerrada de CECATI s/n, Col. Santa Catarina, Del. Azcapotzalco (Mexico)


    Highlights: {yields} PbSe synthesized from PbO instead of Pb powder do not require an inert atmosphere. {yields} During high-energy milling oxygen has to be chemically reduced from the lead oxide. {yields} Solid-state and solid-gas chemical reactions promote both solid and gaseous products. -- Abstract: Both solid-solid and gas-solid reactions have been traced during high-energy milling of Se and PbO powders under vial (P, T) conditions in order to synthesize the PbSe phase. Chemical and thermodynamic arguments are postulated to discern the high-energy milling mechanism to transform PbO-Se micropowders onto PbSe-nanocrystals. A set of reactions were evaluated at around room temperature. Therefore an experimental campaign was designed to test the nature of reactions in the PbO-Se system during high-energy milling.

  12. Amorphous chalcogenide semiconductors for solid state dosimetric systems of high-energetic ionizing radiation

    Shpotyuk, O. [Pedagogical University, Czestochowa (Poland)]|[Institute of Materials, Lvov (Ukraine)


    The application possibilities of amorphous chalcogenide semiconductors use as radiation-sensitive elements of high-energetic (E > 1 MeV) dosimetric systems are analysed. It is shown that investigated materials are characterized by more wide region of registered absorbed doses and low temperature threshold of radiation information bleaching in comparison with well-known analogies based on coloring oxide glasses. (author). 16 refs, 1 tab.

  13. High Power Semiconductor Devices and Solid State Switches for Pulsed Discharge Applications

    Fleischmann, W.; Welleman, A.


    Based on long term experience, collected mainly with military applications like Rail Guns and Active Armour, a range of optimized semiconductor devices for pulsed applications was developed by ABB Switzerland Ltd and described in this presentation. The presented devices are optimized for pulsed discharge and fit very well for switching the short but high electrical power demand used for magnetic forming. Devices are available in different versions with silicon wafer diameters up to 120 mm and...

  14. Huang Kun (1919-2005)A Pioneer of Solid-state and Semiconductor Physics in China


    @@ Prof. Huang Kun made many pioneering contributions in solid-state physics. In the late 1940s, for example, he theoretically predicted diffuse X-ray reflection due to point defects in crystal lattices, which was experimentally confirmed in the 1960s. Known as "Huang Scattering," the theory has already developed into a method for studying micro-defects in solids.

  15. Micro-Encapsulation of Probiotics

    Meiners, Jean-Antoine

    Micro-encapsulation is defined as the technology for packaging with the help of protective membranes particles of finely ground solids, droplets of liquids or gaseous materials in small capsules that release their contents at controlled rates over prolonged periods of time under the influences of specific conditions (Boh, 2007). The material encapsulating the core is referred to as coating or shell.

  16. Semiconductor statistics

    Blakemore, J S


    Semiconductor Statistics presents statistics aimed at complementing existing books on the relationships between carrier densities and transport effects. The book is divided into two parts. Part I provides introductory material on the electron theory of solids, and then discusses carrier statistics for semiconductors in thermal equilibrium. Of course a solid cannot be in true thermodynamic equilibrium if any electrical current is passed; but when currents are reasonably small the distribution function is but little perturbed, and the carrier distribution for such a """"quasi-equilibrium"""" co

  17. Colloidal Sb2S3 Nanocrystals: Synthesis, Characterization and Fabrication of Solid-State Semiconductor Sensitized Solar Cell

    Abulikemu, Mutalifu


    Inorganic nanocrystals composed of earth-abundant and non-toxic elements are crucial to fabricated sustainable photovoltaic devices in large scale. In this study, various-shaped and different phases of antimony sulfide nanocrystals, which is composed of non-scarce and non-toxic elements, are synthesized using hot-injection colloidal method. The effect of various synthetic parameters on the final morphology is explored. Also, foreign ion (Chlorine) effects on the morphology of Sb2S3 nanocrystals have been observed. Structural, optical and morphological properties of the nanocrystals were investigated, and Sb2S3 nanocrystal-based solid-state semiconductor-sensitized solar cells were fabricated using as-prepared nanocrystals. We achieved promising power conversion efficiencies of 1.48%.

  18. In Situ Fabrication of ZnS Semiconductor Nanoparticles in Layered Organic-inorganic Solid Template

    Bao Lin ZHU; Xiao CHEN; Zhen Ming SUI; Li Mei XU; Chun Jie YANG; Ji Kuan ZHAO; Jie LIU


    Ordered ZnS semiconductor nanoparticles were in situ synthesized in metal halide perovskite organic/inorganic layered hybrids (CnH2n+1NH3)2ZnCl4 (n=10 and 12) by reaction of their spin-casting films with H2S gas. Transmission electron microscopy, UV-vis spectroscopy and small-angle X-ray diffraction were used to characterize the morphology and the structure of formed nanoparticles. Obtained results indicate an effective way to incorporate functional inorganic nanoparticles into structured organic matrices.

  19. Highly efficient solid-state synthesis of carbon-encapsulated ultrafine MoO2 nanocrystals as high rate lithium-ion battery anode

    Liu, Boyang; Shao, Yingfeng; Zhang, Yuliang; Zhang, Fuhua; Zhong, Ning; Li, Wenge


    A simple and highly efficient method is developed for the one-step in situ preparation of carbon-encapsulated MoO2 nanocrystals (MoO2@C) with core-shell structure for high-performance lithium-ion battery anode. The synthesis is depending on the solid-state reaction of cyclopentadienylmolybdenum tricarbonyl dimer with ammonium persulfate in an autoclave at 200 °C for 30 min. The large amount of heat generated during the explosive reaction cleaves the cyclopentadiene ligands into small carbon fragments, which form carbon shell after oxidative dehydrogenation coating on the MoO2 nanocrystals, resulting in the formation of core-shell structure. The MoO2 nanocrystals have an equiaxial morphology with an ultrafine diameter of 2-8 nm, and the median size is 4.9 nm. Hundreds of MoO2 nanocrystals are encapsulated together by the worm-like carbon shell, which is amorphous and about 3-5 nm in thickness. The content of MoO2 nanocrystals in the nanocomposite is about 69.3 wt.%. The MoO2@C anode shows stable cyclability and retains a high reversible capacity of 443 mAh g-1 after 50 cycles at a current density of 3 A g-1, owing to the effective protection of carbon shell.

  20. V2O5 encapsulated MWCNTs in 2D surface architecture: Complete solid-state bendable highly stabilized energy efficient supercapacitor device

    Pandit, Bidhan; Dubal, Deepak P.; Gómez-Romero, Pedro; Kale, Bharat B.; Sankapal, Babasaheb R.


    A simple and scalable approach has been reported for V2O5 encapsulation over interconnected multi-walled carbon nanotubes (MWCNTs) network using chemical bath deposition method. Chemically synthesized V2O5/MWCNTs electrode exhibited excellent charge-discharge capability with extraordinary cycling retention of 93% over 4000 cycles in liquid-electrolyte. Electrochemical investigations have been performed to evaluate the origin of capacitive behavior from dual contribution of surface-controlled and diffusion-controlled charge components. Furthermore, a complete flexible solid-state, flexible symmetric supercapacitor (FSS-SSC) device was assembled with V2O5/MWCNTs electrodes which yield remarkable values of specific power and energy densities along with enhanced cyclic stability over liquid configuration. As a practical demonstration, the constructed device was used to lit the ‘VNIT’ acronym assembled using 21 LED’s. PMID:28256550

  1. Solid-state formation of titanium carbide and molybdenum carbide as contacts for carbon-containing semiconductors

    Leroy, W. P.; Detavernier, C.; van Meirhaeghe, R. L.; Kellock, A. J.; Lavoie, C.


    Metal carbides are good candidates to contact carbon-based semiconductors (SiC, diamond, and carbon nanotubes). Here, we report on an in situ study of carbide formation during the solid-state reaction between thin Ti or Mo films and C substrates. Titanium carbide (TiC) was previously reported as a contact material to diamond and carbon nanotubes. However, the present study shows two disadvantages for the solid-state reaction of Ti and C. First, because Ti reacts readily with oxygen, a capping layer should be included to enable carbide formation. Second, the TiC phase can exist over a wide range of composition (about 10%, i.e., from Ti0.5C0.5 to Ti0.6C0.4), leading to significant variations in the properties of the material formed. The study of the Mo-C system suggests that molybdenum carbide (Mo2C) is a promising alternative, since the phase shows a lower resistivity (about 45% lower than for TiC), the carbide forms below 900 °C, and its formation is less sensitive to oxidation as compared with the Ti-C system. The measured resistivity for Mo2C is ρ=59 μΩ cm, and from kinetic studies an activation energy for Mo2C formation of Ea=3.15+/-0.15 eV was obtained.

  2. Aqueous Synthesis of Protein-Encapsulated ZnSe Quantum Dots and Physical Significance of Semiconductor-Induced Cu(II) Ion Sensing.

    Kundu, Somashree; Maiti, Susmita; Ghosh, Debasmita; Roy, Chandra Nath; Saha, Abhijit


    In view of their promising bio-applicability, we have synthesized water-soluble bovine serum albumin (BSA)-encapsulated ZnSe quantum dots (QDs) with visible emission with longer average luminescence lifetimes of approximately 125 ns at ambient conditions. BSA-ZnSe QDs are shown to be efficient selective copper ion probes in the presence of physiologically important metal ions through luminescence quenching with a high Stern-Volmer constant (3.3×10(5)  m(-1) ). The mechanism of sensing has been explained in terms of electron transfer processes and the apparent rate of electron transfer (Ket ) from ZnSe QDs to Cu(2+) has been calculated to be 2.8×10(8)  s(-1) . It is demonstrated that the negative conduction band potential plays a major role in the feasibility of the electron transfer process, which is reflected in the higher efficacy of ZnSe QDs in sensing copper(II) ions over other group II-VI quantum dots, namely, CdSe, ZnS, or CdS. The results observed with cysteine-capped QDs are almost identical to those with BSA-encapsulated QDs and this presumably negates the possible reason of Cu(II) ion induced quenching ascribed to its binding with surface groups or replacement of metal sites as proposed by several groups previously. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. A new polarimeter scheme based on solid state semiconductors Un nuevo esquema para polarímetros basado en semiconductor de estado sólido

    Heiner Castro Gutierrez


    Full Text Available A new kind of polarimeter scheme is suggested using solid state semiconductors. The new approach is based on the modulation over the intensities of the diffracted beams through a two-dimensional chiral grating, reported recently. It will be demonstrated that at least four intensity measurements of no equivalent diffracted beams are needed in order to estimate the polarization state of the incident beam. The incident beam azimuth was varied by routing a linear polarizer lens mounting in a stepped motor. The intensities of four diffracted beams were measured using a screen, a CCD camera and some algorithms running in a computer. The LabVIEW development environment software was used for controlling the hardware and for presenting the results. MATLAB© was used for calculating the intensities of the diffracted beams and computing the azimuth of the incident beam. Although both the azimuth and ellipticity should be estimated, the experiments show that only the azimuth estimation yields accurate results. The ellipticity cannot be estimated with precision. The error on the azimuth estimation depends on the variation in the power of the incident beam. It was found that the azimuth estimation is accurate between [0,140 and (150,180] degrees. The cause of huge errors in the azimuth found between 140 and 150 degrees are kept unknown.Un nuevo esquema de polarímetro es sugerido usando semiconductores de estado sólido. La nueva aproximación está basada en la modulación sobre las intensidades de los rayos difractados a través de una rejilla quiral de dos dimensiones reportado recientemente. Será demostrado que al menos cuatro mediciones de intensidades de rayos difractados no equivalentes son necesarios para estimar el estado de polarización del rayo incidente. El azimut del rayo incidente es variado, rotando un lente polarizador lineal montado en un motor paso a paso. La intensidad de cuatro rayos difractados es medida por medio de una peque

  4. PEG encapsulated by porous triamide-linked polymers as support for solid-liquid phase change materials for energy storage

    Andriamitantsoa, Radoelizo S.; Dong, Wenjun; Gao, Hongyi; Wang, Ge


    A series of porous triamide-linked polymers labeled as PTP were prepared by condensation of 1,3,5-benzenetricarbonyl trichloride with benzene-1,4-diamine (A), 4,4‧-methylenediamine (B) and 1,3,5-triazine-2,4,6-triamine (C) respectively. The as-synthesized polymers exhibit permanent porosity and high surface areas which guarantee to hold polyethylene glycol (PEG) molecules in their network for shape-stabilized phase change materials. They possess different effects on the phase change properties of the composite due to their different porosities. PTP-A have intrinsic well-ordered morphology, microstructure and good enough pores to keep the PCMs compared to PTP-B and PTP-C. PEG 2000 used as PCMs could be retained up to 85 wt% in PTP-A polymer materials and these composites were defined as form-stable composite PCMs without the leakage of melted PCM. The thermal study revealed a good storage effect of encapsulated polymer and the enthalpy of melting increases in the order PTP-C storage capacity. The latent heats for melting and freezing was found to be 155 and 141.7 kJ/kg with a peak appearing at around 53.13 and 29.67 °C respectively. The study suggests that pore size is important for the preparation of shape-stabilized PCMs.

  5. Semiconductor electrochemistry

    Memming, Rüdiger


    Providing both an introduction and an up-to-date survey of the entire field, this text captivates the reader with its clear style and inspiring, yet solid presentation. The significantly expanded second edition of this milestone work is supplemented by a completely new chapter on the hot topic of nanoparticles and includes the latest insights into the deposition of dye layers on semiconductor electrodes. In his monograph, the acknowledged expert Professor Memming primarily addresses physical and electrochemists, but materials scientists, physicists, and engineers dealing with semiconductor technology and its applications will also benefit greatly from the contents.

  6. Preclinical systemic toxicity evaluation of chitosan-solid lipid nanoparticle-encapsulated aspirin and curcumin in combination with free sulforaphane in BALB/c mice

    Thakkar, Arvind; Chenreddy, Sushma; Thio, Astrid; Khamas, Wael; Wang, Jeffrey; Prabhu, Sunil


    Our previous studies have established the efficacy of chemopreventive regimens of aspirin and curcumin (CUR) encapsulated within solid lipid nanoparticles (SLNs) in combination with free sulforaphane (ACS combination) to prevent or delay the initiation and progression of pancreatic cancer, classified as one of the deadliest diseases with very low chances of survival upon diagnosis. Although toxicity of individual drugs and SLN has been studied previously, there are no studies in current literature that evaluate the potential toxicity of a combined regimen of ACS, especially when encapsulated within chitosan-SLNs (c-SLNs). Hence, objective of the current study was to investigate the potential toxic effects of ACS c-SLN combined chemopreventive regimens following acute (3 days), subacute (28 days), and subchronic (90 days) administrations by oral gavage in BALB/c mice. Mice were administered the following regimens: saline, blank c-SLN, low-dose ACS c-SLN (2+4.5+0.16 mg/kg), medium-dose ACS c-SLN (20+45+1.6 mg/kg), and high-dose ACS c-SLN (60+135+4.8 mg/kg). The potential toxicity was evaluated based on animal survival, body weight, hematology, blood chemistry, and organ histopathology. During 3-day, 28-day, and 90-day study periods, no animal deaths were observed. Treatment with ACS c-SLNs did not cause alteration in complete blood counts and blood chemistry data. Histopathological examination of various organ sections (pancreas, heart, liver, kidney, and brain) appeared normal. Based on the results of this study, no signs of toxicity in acute, subacute, and subchronic studies following oral administration of ACS c-SLNs were found indicating that the oral dosing regimens were safe at the levels tested for long-term administration to prevent the onset of pancreatic cancer. PMID:27499621

  7. Preclinical systemic toxicity evaluation of chitosan-solid lipid nanoparticle-encapsulated aspirin and curcumin in combination with free sulforaphane in BALB/c mice.

    Thakkar, Arvind; Chenreddy, Sushma; Thio, Astrid; Khamas, Wael; Wang, Jeffrey; Prabhu, Sunil


    Our previous studies have established the efficacy of chemopreventive regimens of aspirin and curcumin (CUR) encapsulated within solid lipid nanoparticles (SLNs) in combination with free sulforaphane (ACS combination) to prevent or delay the initiation and progression of pancreatic cancer, classified as one of the deadliest diseases with very low chances of survival upon diagnosis. Although toxicity of individual drugs and SLN has been studied previously, there are no studies in current literature that evaluate the potential toxicity of a combined regimen of ACS, especially when encapsulated within chitosan-SLNs (c-SLNs). Hence, objective of the current study was to investigate the potential toxic effects of ACS c-SLN combined chemopreventive regimens following acute (3 days), subacute (28 days), and subchronic (90 days) administrations by oral gavage in BALB/c mice. Mice were administered the following regimens: saline, blank c-SLN, low-dose ACS c-SLN (2+4.5+0.16 mg/kg), medium-dose ACS c-SLN (20+45+1.6 mg/kg), and high-dose ACS c-SLN (60+135+4.8 mg/kg). The potential toxicity was evaluated based on animal survival, body weight, hematology, blood chemistry, and organ histopathology. During 3-day, 28-day, and 90-day study periods, no animal deaths were observed. Treatment with ACS c-SLNs did not cause alteration in complete blood counts and blood chemistry data. Histopathological examination of various organ sections (pancreas, heart, liver, kidney, and brain) appeared normal. Based on the results of this study, no signs of toxicity in acute, subacute, and subchronic studies following oral administration of ACS c-SLNs were found indicating that the oral dosing regimens were safe at the levels tested for long-term administration to prevent the onset of pancreatic cancer.

  8. Chemical preparation of crystalline, nonmolecular solids, including solution-liquid-solid (SLS) growth of semiconductor fibers and varied routes to nanocrystalline molybdenum disilicide

    Trentler, Timothy John

    New methods for the preparation of crystalline, nonmolecular solids under milder conditions and/or with control of crystallite size or morphology were developed in two separate projects. In one project, polycrystalline 13-15 semiconductor fibers (dimensions 10-100 nm x 50-1000 nm) were grown by solution-based chemical methods. Crystal precursor species of the general formula (Rsb{x}InEHsb{x}rbracksb{n}, where E is a pnictide and R is an alkyl group, were prepared by the phosphinolysis or arsinolysis of alkylindanes in aromatic solvents. Thermal decomposition of these precursors in solution, which was catalyzed by various protic reagents (MeOH, PhSH, Etsb2NH, or PhCOsb2H), resulted in crystalline InE when In metal was present in the form of submicron droplets dispersed in the solvent. Crystallization was determined to occur (at the lowest temperatures reported for 13-15 semiconductors, liquid-solid (SLS) mechanism reminiscent of vapor-liquid-solid (VLS) growth of single-crystal whiskers. Some analogous reactions were investigated in which t-Busb3Ga was mixed with the alkylindane in order to prepare ternary alloys (Insb{x}Gasb{1-x}As). Product crystallinity and composition was dependent on, though not exclusively determined by, the indane/gallane ratio. Crystals with composition within the miscibility gap for this alloy system were grown. The focus of the other project was the preparation of nanocrystalline (crystallite dimensions NaK alloy in an ultrasonically agitated hydrocarbon solvent followed by thermal processing (900sp°C) under vacuum to eliminate byproduct salts. MoSisb2 crystallites averaging 20-50 nm were obtained. Solvent degradation during this process resulted in the incorporation of substantial carbonaceous impurity (believed to be SiC) in these products. To eliminate the carbon, similar solventless reductions (without ultrasound) were conducted in molten magnesium, but average particle sizes have not been refined into the nanometer regime (currently

  9. Solution-Processed Ambipolar Organic Thin-Film Transistors by Blending p- and n-Type Semiconductors: Solid Solution versus Microphase Separation.

    Xu, Xiaomin; Xiao, Ting; Gu, Xiao; Yang, Xuejin; Kershaw, Stephen V; Zhao, Ni; Xu, Jianbin; Miao, Qian


    Here, we report solid solution of p- and n-type organic semiconductors as a new type of p-n blend for solution-processed ambipolar organic thin film transistors (OTFTs). This study compares the solid-solution films of silylethynylated tetraazapentacene 1 (acceptor) and silylethynylated pentacene 2 (donor) with the microphase-separated films of 1 and 3, a heptagon-embedded analogue of 2. It is found that the solid solutions of (1)x(2)1-x function as ambipolar semiconductors, whose hole and electron mobilities are tunable by varying the ratio of 1 and 2 in the solid solution. The OTFTs of (1)0.5(2)0.5 exhibit relatively balanced hole and electron mobilities comparable to the highest values as reported for ambipolar OTFTs of stoichiometric donor-acceptor cocrystals and microphase-separated p-n bulk heterojunctions. The solid solution of (1)0.5(2)0.5 and the microphase-separated blend of 1:3 (0.5:0.5) in OTFTs exhibit different responses to light in terms of absorption and photoeffect of OTFTs because the donor and acceptor are mixed at molecular level with π-π stacking in the solid solution.

  10. Quasi-soliton generation in solid-state lasers with semiconductor saturable absorber

    Palihati Mijeti(帕力哈提·米吉提); Tursunjan Ablekim(吐尔逊江·阿布力克木)


    Recent advances in ultrafast, ultra-short solid-state lasers have resulted in sub-6 fs pulses generated directly from the cavity of Ti:sapphire lasers. The generation of extremely short pulses is possible due to the formation of a quasi-Schrodinger soliton. Our investigation is directed to the peculiarities of the transition between femtosecond to picosecond generation. We found that the above transition is accompanied by the threshold and hysteresis phenomena. On the basis of soliton perturbation theory, the numerical simulation studying two different experimental situations has been performed, the first situation corresponds to the study of the lasers field's parameters under variation of control parameters (dispersion or pump power), the second one is for continuous variation of control parameter within a single generation session. Physically it corresponds to not repeated laser session but the variation of control parameter when the pulse has formed already.

  11. Solid-state nanoparticle coated emulsions for encapsulation and improving the chemical stability of all-trans-retinol.

    Ghouchi-Eskandar, Nasrin; Simovic, Spomenka; Prestidge, Clive A


    Submicron oil-in-water (o/w) emulsions stabilised with conventional surfactants and silica nanoparticles were prepared and freeze-dried to obtain free-flowing powders with good redispersibility and a three-dimensional porous matrix structure. Solid-state emulsions were characterised for visual appearance, particle size distribution, zeta potential and reconstitution properties after freeze-drying with various sugars and at a range of sugar to oil ratios. Comparative degradation kinetics of all-trans-retinol from freeze-dried and liquid emulsions was investigated as a function of storage temperatures. Optimum stability was observed for silica-coated oleylamine emulsions at 4 °C in their wet state. The half-life of all-trans-retinol was 25.66 and 22.08 weeks for silica incorporation from the oil and water phases respectively. This was ∼4 times higher compared to the equivalent solid-state emulsions with drug half-life of 6.18 and 6.06 weeks at 4 °C. Exceptionally, at a storage temperature of 40 °C, the chemical stability of the drug was 3 times higher in the solid-state compared to the wet emulsions which confirmed that freeze-drying is a promising approach to improve the chemical stability of water-labile compounds provided that the storage conditions are optimised.

  12. The effect of cetyl palmitate crystallinity on physical properties of gamma-oryzanol encapsulated in solid lipid nanoparticles

    Ruktanonchai, Uracha; Sakulkhu, Usawadee [National Nanotechnology Center, National Science and Technology Development Agency, 111 Thailand Science Park, Paholyothin Road, Klong 1, Klong Luang, Pathumthani 12120 (Thailand); Limpakdee, Surachai; Meejoo, Siwaporn [Department of Chemistry, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400 (Thailand); Bunyapraphatsara, Nuntavan [Department of Pharmacognosy, Faculty of Pharmacy, Mahidol University, Sri-ayudhya Road, Bangkok 10400 (Thailand); Junyaprasert, Varaporn [Department of Pharmacy, Faculty of Pharmacy, Mahidol University, Sri-ayudhya Road, Bangkok 10400 (Thailand); Puttipipatkhachorn, Satit [Department of Manufacturing Pharmacy, Faculty of Pharmacy, Mahidol University, Sri-ayudhya Road, Bangkok 10400 (Thailand)], E-mail:


    This present study was aimed at investigating the effect of the crystallinity of cetyl palmitate based solid lipid nanoparticles (SLNs) on the physical properties of {gamma}-oryzanol-loaded SLNs. SLNs consisting of varying ratios of cetyl palmitate and {gamma}-oryzanol were prepared. Their hydrodynamic diameters were in the range 210-280 nm and the zeta potentials were in the range -27 to -35 mV. The size of SLNs increased as the amount of cetyl palmitate decreased whereas no significant change of zeta potentials was found. Atomic force microscopy pictures indicated the presence of disc-like particles. The crystallinity of SLNs, determined by differential scanning calorimetry and powder x-ray diffraction, was directly dependent on the ratio of cetyl palmitate to {gamma}-oryzanol and decreased with decreasing cetyl palmitate content in the lipid matrix. Varying this ratio in the lipid mix resulted in a shift in the melting temperature and enthalpy, although the SLN structure remained unchanged as an orthorhombic lamellar lattice. This has been attributed to a potential inhibition by {gamma}-oryzanol during lipid crystal growth as well as a less ordered structure of the SLNs. The results revealed that the crystallinity of the SLNs was mainly dependent on the solid lipid, and that the crystallinity has an important impact on the physical characteristics of active-loaded SLNs.

  13. Stable vapor transportation of solid sources in MOVPE of III V compound semiconductors

    Shenai-Khatkhate, Deodatta V.; DiCarlo, Ronald L.; Marsman, Charles J.; Polcari, Robert F.; Ware, Robert A.; Woelk, Egbert


    Trimethylindium (TMI), in spite of being a solid, has remained the precursor of choice for the deposition of indium containing layers by MOVPE. However, maintaining stable TMI flows and constant concentrations in gas phase during the growth still continue to be a major concern in MOVPE. This issue is further compounded by lower TMI consumptions achieved as the MOVPE growth conditions become increasingly more aggressive to meet the industry demand of higher throughputs, e.g. at higher flow rates, or at reduced pressures or when TMI source is maintained at higher temperatures. In this paper, we report our new findings of improved TMI delivery (>90, and in some cases >95%) with excellent stability of TMI concentration throughout the cylinder lifetime. These results are achieved using standard fill capacity and under intentionally set aggressive conditions of pressure, temperature and flow. We report a novel delivery technology (Uni-Flo™ II cylinder) that is customer proven and comprises innovative improvements to our dip-tube-less cylinder design, Uni-Flo™ cylinder, and advancements in TMI packaging. In this report, TMI depletion rates are examined over an extensive range of operating parameters currently employed in MOVPE, viz. flow rates ranging from 100 to 1000 sccm, source temperatures between 17 and 30 °C, and reactor pressures in the range 300-1000 mbar. We report, significant improvements in TMI delivery (>95% depletion) at higher molar flux of TMI (>3 g/h) and an excellent reproducible dosimetry of TMI with no batch-to-batch variation, by using Uni-Flo™ II cylinder as the enabling solution to TMI delivery problems.

  14. Encapsulation, solid-phases identification and leaching of toxic metals in cement systems modified by natural biodegradable polymers.

    Lasheras-Zubiate, M; Navarro-Blasco, I; Fernández, J M; Alvarez, J I


    Cement mortars loaded with Cr, Pb and Zn were modified by polymeric admixtures [chitosans with low (LMWCH), medium (MMWCH) and high (HMWCH) molecular weight and hydroxypropylchitosan (HPCH)]. The influence of the simultaneous presence of the heavy metal and the polymeric additive on the fresh properties (consistency, water retention and setting time) and on the compressive strength of the mortars was assessed. Leaching patterns as well as properties of the cement mortars were related to the heavy metals-bearing solid phases. Chitosan admixtures lessened the effect of the addition of Cr and Pb on the setting time. In all instances, chitosans improved the compressive strength of the Zn-bearing mortars yielding values as high as 15 N mm(-2). A newly reported Zn phase, dietrichite (ZnAl(2)(SO(4))(4)·22H(2)O) was identified under the presence of LMWCH: it was responsible for an improvement by 24% in Zn retention. Lead-bearing silicates, such as plumalsite (Pb(4)Al(2)(SiO(3))(7)), were also identified by XRD confirming that Pb was mainly retained as a part of the silicate network after Ca ion exchange. Also, the presence of polymer induced the appearance and stabilization of some Pb(IV) species. Finally, diverse chromate species were identified and related to the larger leaching values of Cr(VI).

  15. In situ solid state polymerization and characterization of poly (N-vinylcarbazole) encapsulated Keggin type polyoxometalate nanocomposite

    Hazra, Dipak K.; Chatterjee, Rajarshi


    In situ solid state polymerization method was performed with mixtures of polyoxometalate (POM) and N-vinylcarbazole (NVC) in desired weight ratios for the synthesis of nanocomposites. The yield of the PNVC-H4SiW12O40 nanocomposite increased with increasing amount of H4SiW12O40 as well as with [H4SiW12O40]/[PNVC] loadings. The formation of PNVC in the system was endorsed by FTIR, UV-vis, and 1H1 NMR spectroscopic analyses. HRTEM studies revealed that the PNVC-H4SiW12O40 nanoparticles have an average grain size of 62.13 nm and that the H4SiW12O40 nanoparticles are fairly well-dispersed in the composite matrix. SEM analysis shows the presence of agglomerates of nano particles embedded in the matrix. AC conductivity (σac)-frequency variation was constant for PNVC but showed an increasing trend with higher H4SiW12O40:PNVC weight ratios in the composite.

  16. Folic acid functionalized long-circulating co-encapsulated docetaxel and curcumin solid lipid nanoparticles: In vitro evaluation, pharmacokinetic and biodistribution in rats.

    Pawar, Harish; Surapaneni, Sunil Kumar; Tikoo, Kulbhushan; Singh, Charan; Burman, Rohani; Gill, Manjinder Singh; Suresh, Sarasija


    The purpose of this study was to develop folic acid functionalized long-circulating co-encapsulated docetaxel (DTX) and curcumin (CRM) solid lipid nanoparticles (F-DC-SLN) to improve the pharmacokinetic and efficacy of DTX therapy. F-DC-SLN was prepared by hot melt-emulsification method and optimized by face centered-central composite design (FC-CCD). The SLN was characterized in terms of size and size distribution, drug entrapment efficiency and release profile. The cytotoxicity and cell uptake of the SLN formulations were evaluated in MCF-7 and MDA-MB-231 cell lines. The in vivo pharmacokinetic and biodistribution were studied in Wistar rats. F-DC-SLN exhibited 247.5 ± 3.40 nm particle size with 73.88 ± 1.08% entrapment efficiency and zeta potential of 14.53 ± 3.6 mV. Transmission electron microscopy (TEM) revealed spherical morphology of the SLN. Fluorescence microscopy confirmed the targeting efficacy of F-DC-SLN in MCF-7 cells. F-DC-SLN exhibited a significant increase in area under the curve (594.21 ± 64.34 versus 39.05 ± 7.41 μg/mL h) and mean residence time (31.14 ± 19.94 versus 7.24 ± 4.51 h) in comparison to Taxotere®. In addition, decreased DTX accumulation from F-DC-SLN in the heart and kidney in comparison to Taxotere may avoid to toxicity these vital organs. In conclusion, the F-DC-SLN improved the efficacy and pharmacokinetic profile of DTX exhibiting enhanced potential in optimizing breast cancer therapy.

  17. Formation of ion pairing as an alternative to improve encapsulation and anticancer activity of all-trans retinoic acid loaded in solid lipid nanoparticles

    Carneiro G


    Full Text Available Guilherme Carneiro,1 Elton Luiz Silva,1 Layssa Alves Pacheco,1 Elaine Maria de Souza-Fagundes,2 Natássia Caroline Resende Corrêa,3 Alfredo Miranda de Goes,3 Mônica Cristina de Oliveira,1 Lucas Antônio Miranda Ferreira11Department of Pharmaceutics, Faculty of Pharmacy, Federal University of Minas Gerais, Belo Horizonte, Brazil; 2Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil; 3Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, BrazilAbstract: This work aims to develop solid lipid nanoparticles (SLNs loaded with retinoic acid (RA to evaluate the influence of two lipophilic amines, stearylamine (SA and benethamine (BA, and one hydrophilic, triethylamine (TA, on drug-encapsulation efficiency (EE and cytotoxicity in cancer cell lines. The SLNs were characterized for EE, size, and zeta potential. The mean particle size decreased from 155 ± 1 nm (SLNs without amine to 104 ± 4, 95 ± 1, and 96 ± 1 nm for SLNs prepared with SA, BA, and TA, respectively. SA-RA-loaded SLNs resulted in positively charged particles, whereas those with TA and BA were negatively charged. The EEs were significantly improved with the addition of the amines, and they increased from 36% ± 6% (without amine to 97% ± 2%, 90% ± 2%, and 100% ± 1% for SA, TA, and BA, respectively. However, stability studies showed higher EE for BA-RA-loaded SLNs than TA-RA-loaded SLNs after 30 days. The formulations containing SA loaded or unloaded (blank SLNs with RA were cytotoxic in normal and cancer cell lines. In contrast, the blank SLNs containing TA or BA did not show cytotoxicity in human breast adenocarcinoma cells (MCF-7, while RA-loaded SLNs with the respective amines were significantly more cytotoxic than free RA. Furthermore, the cytotoxicity of BA-RA-loaded SLNs was significantly higher than TA-RA-loaded SLNs. These

  18. Preparation of Si sub 1 sub - sub x sub - sub y Ge sub x C sub y semiconductor films on Si by ion implantation and solid phase epitaxy

    Liu Xue Qin; Zhen Cong Mian; Zhang Jing; Yang Yi; Guo Yong


    Si sub 1 sub - sub x sub - sub y Ge sub x C sub y ternary alloy semiconductor films were prepared on Si(100) substrates by C ion implanting SiGe films and subsequent solid phase epitaxy (SPE). Two-step annealing technique was employed in the SPE processing. The properties of the alloy films were determined using Rutherford backscattering spectroscopy (RBS), Fourier transform infrared spectroscopy (FTIR) and High-resolution x-ray diffraction (HRXRD) measurements. It is shown that C atoms are located at substitutional sites and the incorporation of C relieves the compressive strain in the SiGe layer

  19. The 3-5 semiconductor solid solution single crystal growth. [low gravity float zone growth experiments using gallium indium antimonides and cadmium tellurides

    Gertner, E. R.


    Techniques used for liquid and vapor phase epitaxy of gallium indium arsenide are described and the difficulties encountered are examined. Results show that the growth of bulk III-V solid solution single crystals in a low gravity environment will not have a major technological impact. The float zone technique in a low gravity environment is demonstrated using cadmium telluride. It is shown that this approach can result in the synthesis of a class of semiconductors that can not be grown in normal gravity because of growth problems rooted in the nature of their phase diagrams.

  20. Analytical challenges of determining composition and structure in small volumes with applications to semiconductor technology, nanostructures and solid state science

    Ma, Zhiyong; Kuhn, Markus; Johnson, David C.


    Determining the structure and composition of small volumes is vital to the ability to understand and control nanoscale properties and critical for advancing both fundamental science and applications, such as semiconductor device manufacturing. While metrology of nanoscale materials (nanoparticles, nanocomposites) and nanoscale semiconductor structures is challenging, both basic research and cutting edge technology benefit from new and enhanced analytical techniques. This focus issue contains articles describing approaches to overcome the challenges in obtaining statistically significant atomic-scale quantification of structure and composition in a variety of materials and devices using electron microscopy and atom probe tomography.

  1. High Electron Mobility Ge n-Channel Metal-Insulator-Semiconductor Field-Effect Transistors Fabricated by the Gate-Last Process with the Solid Source Diffusion Technique

    Maeda, Tatsuro; Morita, Yukinori; Takagi, Shinichi


    We fabricate high-k/Ge n-channel metal-insulator-semiconductor field-effect transistors (MISFETs) by the gate-last process with the thermal solid source diffusion to achieve both of high quality source/drain (S/D) and gate stack. The n+/p junction formed by solid source diffusion technique of Sb dopant shows the excellent diode characteristics of ˜1.5×105 on/off ratio between +1 and -1 V and the quite low reverse current density of ˜4.1×10-4 A/cm2 at +1 V after the fabrication of high-k/Ge n-channel MISFETs that enable us to observe well-behaved transistor performances. The extracted electron mobility with the peak of 891 cm2/(V.s) is high enough to be superior to the Si universal electron mobility especially in low Eeff.

  2. Method of doping a semiconductor

    Yang, Chiang Y.; Rapp, Robert A.


    A method for doping semiconductor material. An interface is established between a solid electrolyte and a semiconductor to be doped. The electrolyte is chosen to be an ionic conductor of the selected impurity and the semiconductor material and electrolyte are jointly chosen so that any compound formed from the impurity and the semiconductor will have a free energy no lower than the electrolyte. A potential is then established across the interface so as to allow the impurity ions to diffuse into the semiconductor. In one embodiment the semiconductor and electrolyte may be heated so as to increase the diffusion coefficient.

  3. Handbook of luminescent semiconductor materials

    Bergman, Leah


    Photoluminescence spectroscopy is an important approach for examining the optical interactions in semiconductors and optical devices with the goal of gaining insight into material properties. With contributions from researchers at the forefront of this field, Handbook of Luminescent Semiconductor Materials explores the use of this technique to study semiconductor materials in a variety of applications, including solid-state lighting, solar energy conversion, optical devices, and biological imaging. After introducing basic semiconductor theory and photoluminescence principles, the book focuses

  4. Synthesis and characterization by solid-state impedance spectroscopy of semiconductor Cu2ZnSnS4 material for photovoltaic technologies

    Muñoz, M.; Vera-López, E.; Gómez-Cuaspud, J. A.; Pineda-Triana, Y.


    Current work is focused on the synthesis and characterization of a Cu2ZnSnS4 material (Abbreviated CZTS), identified as a potential candidate for the manufacture of photovoltaic cells. The material was obtained by means of a hydrothermal route which permits a simple and economical alternative to synthesize advanced materials for photovoltaic applications. The synthesis of a solid started from corresponding metal nitrates of Cu(NO3)2.6H2O, Zn(NO3)2, Sn(NO3)4.6H2O and thiourea as S source, which were dissolved in deionized water until complete a 1.0mol L-1 concentration. The solution was kept in a Teflon lined steel vessel with magnetic stirring (150 rpm) and treated at 300°C for 12 hours to form the crystalline phase. The initial characterization of solid was done using UV spectroscopy to validate the chemical process and identify the corresponding Band-gap around (1.43eV). The structural characterization by X-ray diffraction, confirmed the presence of nanometric solids (140-260nm). The morphological characterization by SEM analysis evidenced a homogeneous material in the form of micrometric aggregates, by a related synthesis method. Finally, the electrical characterization by means of solid state impedance spectroscopy demonstrated a semiconductor behaviour which evidenced the transport phenomena associated with a Warburg resistance.

  5. Photoprocess of molecules encapsulated in porous solids X: Photosensitization of zeolite-Y encapsulated tris(2,2'-bipyridine-nickel-(II)ion by phenosafranine adsorbed onto the external surface of the nanoporous host

    Karuppannan Senthil Kumar; Sudha T; Paramasivam Natarajan


    Tris-(2,2'-bipyridine)-nickel-(II) complex ion encapsulated by zeolite-Y host has been synthesized by ship-in-a-bottle method. Photosensitization of nickel(II) complex (Ni(bpy)$^{2+}_{3}$) in the zeolite host by surface adsorbed phenosafranine dye was investigated by time-resolved fluorescence and absorption spectral measurements. Formation of nickel (II)-complex in the super cage of the host was ascertained by XRD, FTIR, solidstate NMR, diffuse reflectance UV-visible absorption spectroscopic techniques and ICP-OES measurements. Phenosafranine dye adsorbed on the external surface of zeolite-Y shows a decrease in fluorescence intensity with increased loading of the nickel(II) complex in zeolite-Y. Time-resolved emission studies show two excited state lifetimes for the photoexcited phenosafranine dye. Average fluorescence lifetimes of the dye in this case do not change with increase in the loading of the nickel(II) complex. However, relative contribution of short lifetime component increases when the amount of encapsulated nickel(II) complex is increased. The zeolite-Y host containing only bipyridyl ligand shows a marked decrease in fluorescence intensity. Fluorescence lifetimes of the dye however do not change with increased loading of bipyridyl while relative contribution of short lifetime component increases with an increase in the loading of bipyridyl in the host. This observation is interpreted to be due to electron transfer from the excited state of phenosafranine dye to the bipyridine. Picosecond pump-probe investigations confirm that the photoinduced electron transfer occurs from the surfaceadsorbed phenosafranine in the excited state to the nickel(II) complex within zeolite-Y cavity and also to the Ni(bpy)$^{2+}_{3}$ complex in contact with the phenosafranine dye co-adsorbed on the external surface of the host.

  6. Modification of polyethylene glycol onto solid lipid nanoparticles encapsulating a novel chemotherapeutic agent (PK-L4 to enhance solubility for injection delivery

    Fang YP


    Full Text Available Yi-Ping Fang,1 Pao-Chu Wu,2 Yaw-Bin Huang,3 Cherng-Chyi Tzeng,4 Yeh-Long Chen,4 Yu-Han Hung,2 Ming-Jun Tsai,5,6 Yi-Hung Tsai31Department of Biotechnology, Yuanpei University, Hsinchu, Taiwan; 2School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan; 3Graduate Institute of Clinical Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan; 4School of Medicinal and Applied Chemistry, College of Life Science, Kaohsiung Medical University, Kaohsiung, Taiwan; 5Department of Neurology, China Medical University Hospital, Taichung, Taiwan; 6School of Medicine, Medical College, China Medical University, Taichung, TaiwanBackground: The synthetic potential chemotherapeutic agent 3-Chloro-4-[(4-methoxyphenylamino]furo[2,3-b]quinoline (PK-L4 is an analog of amsacrine. The half-life of PK-L4 is longer than that of amsacrine; however, PK-L4 is difficult to dissolve in aqueous media, which is problematic for administration by intravenous injection.Aims: To utilize solid lipid nanoparticles (SLNs modified with polyethylene glycol (PEG to improve the delivery of PK-L4 and investigate its biodistribution behavior after intravenous administration.Results: The particle size of the PK-L4-loaded SLNs was 47.3 nm and the size of the PEGylated form was smaller, at 28 nm. The entrapment efficiency (EE% of PK-L4 in SLNs with and without PEG showed a high capacity of approximately 100% encapsulation. Results also showed that the amount of PK-L4 released over a prolonged period from SLNs both with and without PEG was comparable to the non-formulated group, with 16.48% and 30.04%, respectively, of the drug being released, which fit a zero-order equation. The half-maximal inhibitory concentration values of PK-L4-loaded SLNs with and those without PEG were significantly reduced by 45%–64% in the human lung carcinoma cell line (A549, 99% in the human breast adenocarcinoma cell line with estrogen receptor (MCF7, and 95% in

  7. Onset of itinerant ferromagnetism associated with semiconductor-metal transition in TiNb1-CoSn half Heusler solid solution compounds

    M A Kouacou; A A Koua; J T Zoueu; K Konan; J Pierre


    In this paper, the magnetic and transport properties of the TiNb1−CoSn solid solution compounds with half Heusler cubic MgAgAs-type structure have been studied. This work shows the onset of ferromagnetism associated with a semiconductor to metal transition. The transition occurs directly from ferromagnetic metal to semiconducting state as it is the case in the TiCoNi1−Sn series studied previously. A weak quantity of Ti in NbCoSn is sufficient to allow the appearance of ferromagnetic order and metallic state. The variations of the Curie temperature as a function of saturation and effective paramagnetic moments are related to the itinerant ferromagnetism model. A comparison is made with the TiCoSnSb1− series (also studied previously), where the transition from TiCoSn ferromagnetic metal to non-magnetic semiconductor TiCoSb occurs through an intermediate metallic Pauli-like state.

  8. Isotopically controlled semiconductors

    Haller, E.E.


    A review of recent research involving isotopically controlled semiconductors is presented. Studies with isotopically enriched semiconductor structures experienced a dramatic expansion at the end of the Cold War when significant quantities of enriched isotopes of elements forming semiconductors became available for worldwide collaborations. Isotopes of an element differ in nuclear mass, may have different nuclear spins and undergo different nuclear reactions. Among the latter, the capture of thermal neutrons which can lead to neutron transmutation doping, can be considered the most important one for semiconductors. Experimental and theoretical research exploiting the differences in all the properties has been conducted and will be illustrated with selected examples. Manuel Cardona, the longtime editor-in-chief of Solid State Communications has been and continues to be one of the major contributors to this field of solid state physics and it is a great pleasure to dedicate this review to him.

  9. Physics of semiconductor lasers

    Mroziewicz, B; Nakwaski, W


    Written for readers who have some background in solid state physics but do not necessarily possess any knowledge of semiconductor lasers, this book provides a comprehensive and concise account of fundamental semiconductor laser physics, technology and properties. The principles of operation of these lasers are therefore discussed in detail with the interrelations between their design and optical, electrical and thermal properties. The relative merits of a large number of laser structures and their parameters are described to acquaint the reader with the various aspects of the semiconductor l

  10. Semiconductors bonds and bands

    Ferry, David K


    As we settle into this second decade of the twenty-first century, it is evident that the advances in micro-electronics have truly revolutionized our day-to-day lifestyle. The technology is built upon semiconductors, materials in which the band gap has been engineered for special values suitable to the particular application. This book, written specifically for a one semester course for graduate students, provides a thorough understanding of the key solid state physics of semiconductors. It describes how quantum mechanics gives semiconductors unique properties that enabled the micro-electronics revolution, and sustain the ever-growing importance of this revolution.

  11. 异甘草素固体脂质纳米粒包封率测定方法的研究%Determination Method of Encapsulation Efficiency of Isoliquiritigenin Solid Lipid Nanoparticles

    陈卫军; 袁勇; 王鲁妹; 智永刚


    目的:建立异甘草素固体脂质纳米粒(ISO-SLN)包封率测定方法.方法:采用透析法分离样品中的游离药物及载药固体脂质纳米粒,并确定透析介质和透析时间;紫外分先光度法测定包封率,检测波长为396nm.结果:以2%泊洛沙姆188水溶液为透析介质、透析时间为8h,能有效分离ISO-SLN与游离ISO,加样回收率大于95%;ISO检测浓度线性范围为1.12~7.84 μg·mL-1(γ=0.999 5),低、中、高浓度平均回收率为99.54%、99.11%、100.2%,RSD均小于5%;3批ISO-SLN平均包封率为80.2%.结论:所建立的方法可用于测定ISO-SLN包封率,且方法准确、简便.%OBJECTIVE: To establish the method for encapsulation efficiency determination of Isoliquiritigenin solid lipid nanoparticles (ISO-SLN).METHODS: Dialysis method was used to isolate free fraction and drug-loading solid lipid nanoparticles from samples.Medium and time of dialysis were confirmed.The encapsulation efficiency was determined by UV spectrophotometry at detection wavelength of 396 nm.RESULTS: 2% poloxamer188 hydrate medium was used as dialysis medium and dialysis time was 8 h.Free ISO could be effectively separated from ISO-SLN by dialysis method.The recovery rate was more than 95%.The linear range of ISO was 1.12~7.84 μg·mL-1(r=-0.999 5) with average recoveries of 99.54%, 99.11% and 100.2% at low, medium and high concentrations (RSD<5%).The encapsulation efficiency of 3 batches of ISO-SLN was 80.2% averagely.CONCLUSION: The method is accurate and simple for encapsulation efficiency determination of ISO-SLN.

  12. Power semiconductors

    Kubát, M


    The book contains a summary of our knowledge of power semiconductor structures. It presents first a short historic introduction (Chap. I) as well as a brief selection of facts from solid state physics, in particular those related to power semiconductors (Chap. 2). The book deals with diode structures in Chap. 3. In addition to fundamental facts in pn-junction theory, the book covers mainly the important processes of power structures. It describes the emitter efficiency and function of microleaks (shunts). the p +p and n + n junctions, and in particular the recent theory of the pin, pvn and p1tn junctions, whose role appears to be decisive for the forward mode not only of diode structures but also of more complex ones. For power diode structures the reverse mode is the decisive factor in pn-junction breakdown theory. The presentation given here uses engineering features (the multiplication factor M and the experimentally detected laws for the volume and surface of crystals), which condenses the presentation an...

  13. Ab initio Assessment of Bi1-xRExCuOS (RE=La, Gd, Y, Lu) Solid Solution as Semiconductor for Photochemical Water Splitting

    Lardhi, Sheikha F.


    The investigation of BiCuOCh (Ch = S, Se and Te) semiconductors family for thermoelectric or photovoltaic materials is an increasing topic of research. These materials can also be considered for photochemical water splitting if one representative having a bandgap, Eg, around 2 eV can be developed. With this aim, we simulated the solid solution Bi1-xRExCuOS (RE = Y, La, Gd and Lu) from pure BiCuOS (Eg~1.1 eV) to pure RECuOS compositions (Eg~2.9 eV) by DFT calculations based on the HSE06 range-separated hybrid functional with inclusion of spin-orbit coupling. Starting from the thermodynamic stability of the solid solution, a large variety of properties were computed for each system including bandgap, dielectric constants, effective masses and exciton binding energies. We discussed the variation of these properties based on the relative organization of Bi and RE atoms in their common sublattice to offer a physical understanding of the influence of the RE doping of BiCuOS. Some compositions were found to give appropriate properties for water splitting application. Furthermore, we found that at low RE fractions the transport properties of BiCuOS are improved that can find applications beyond water splitting.

  14. Semiconductor opto-electronics

    Moss, TS; Ellis, B


    Semiconductor Opto-Electronics focuses on opto-electronics, covering the basic physical phenomena and device behavior that arise from the interaction between electromagnetic radiation and electrons in a solid. The first nine chapters of this book are devoted to theoretical topics, discussing the interaction of electromagnetic waves with solids, dispersion theory and absorption processes, magneto-optical effects, and non-linear phenomena. Theories of photo-effects and photo-detectors are treated in detail, including the theories of radiation generation and the behavior of semiconductor lasers a

  15. Experimental and first-principles studies of high-pressure effects on the structural, electronic, and optical properties of semiconductors and lanthanide doped solids

    Brik, Mikhail G.; Mahlik, Sebastian; Jankowski, Dawid; Strak, Pawel; Korona, Krzysztof P.; Monroy, Eva; Krukowski, Stanislaw; Kaminska, Agata


    In this paper we present a broad overview of our recent experimental and theoretical results obtained for different types of materials: CdTe and CuGa1- x In x S2 chalcopyrite semiconductors, GaN/AlN wide band gap semiconductor quantum wells, and lanthanide-doped dielectric materials. The analysis of pressure-induced phase transitions, variations of the band gaps, refractive index and the pressure dependence of optical properties of these materials is discussed. The presented results show that the high pressure technique is a very useful tool for scientific research and development of of light-emitting technologies. It allows for identification of radiative recombination mechanisms in solid-state light emitters. In polar III-nitride semiconductors, ab initio calculations revealed that the pressure-induced change of the band gap plays minor role, whereas the built-in electric field in heterostructures increases with pressure thus affecting their basic physical properties, i.e., producing a large red-shift of the photoluminescence and lowering the quantum efficiency due to the quantum confined Stark effect. For wide (>4 nm) quantum wells, the reduction of the band-to-band emission efficiency leads to deep defect dominant emission which is almost pressure independent. The observed behavior proves that pressure investigations combined with ab initio calculations can identify the nature of the optical transitions and the main physical factors affecting the radiative efficiency in polar quantum well systems. Furthermore, high pressure studies of the emission and excitation spectra of Y2O2S doped with Tb3+ and Eu3+ allowed estimating the energies of the ground states of all divalent and trivalent lanthanide ions in respect to the valence and conduction band edges of the Y2O2S host. Band gap energy and difference between energies of the ground states of lanthanide ions and band edges have been calculated as a function of pressure. It is shown that pressure causes an

  16. Designed Functional Systems for High-Performance Lithium-Ion Batteries Anode: From Solid to Hollow, and to Core-Shell NiCo2O4 Nanoparticles Encapsulated in Ultrathin Carbon Nanosheets.

    Peng, Liang; Zhang, Huijuan; Fang, Ling; Bai, Yuanjuan; Wang, Yu


    Binary metal oxides have been considered as ideal and promising anode materials, which can ameliorate and enhance the electrochemical performances of the single metal oxides, such as electronic conductivity, reversible capacity, and structural stability. In this research, we report a rational method to synthesize some novel sandwich-like NiCo2O4@C nanosheets arrays for the first time. The nanostructures exhibit the unique features of solid, hollow, and even core-shell NiCo2O4 nanoparticles encapsulated inside and a graphitized carbon layers coating outside. Compared to the previous reports, these composites demonstrate more excellent electrochemical performances, including superior rate capability and excellent cycling capacity. Therefore, the final conclusion would be given that these multifarious sandwich-like NiCo2O4@C composites could be highly qualified candidates for lithium-ion battery anodes in some special field, in which good capability and high capacity are urgently required.

  17. Semiconductor statistics

    Blakemore, J S


    In-depth exploration of the implications of carrier populations and Fermi energies examines distribution of electrons in energy bands and impurity levels of semiconductors. Also: kinetics of semiconductors containing excess carriers, particularly in terms of trapping, excitation, and recombination.

  18. Single-walled carbon nanotubes oust graphene and semiconductor saturable absorbers in Q-switched solid-state lasers at 2 µm

    Mateos, Xavier; Loiko, Pavel; Choi, Sun Young; Rotermund, Fabian; Aguiló, Magdalena; Díaz, Francesc; Griebner, Uwe; Petrov, Valentin


    The superior performance of a saturable absorber (SA) based on randomly-oriented single-walled carbon nanotubes (SWCNTs) operating in the spectral region of their first fundamental transition E 11 over a graphene-SA containing several (n  =  3) carbon layers and a commercial semiconductor SA (SESA) for passive Q-switching of bulk thulium solid-state lasers is demonstrated. Using SWCNT-SA in a compact diode-pumped Tm:KLuW laser, a maximum average output power of 1.36 W is achieved at 1932-1944 nm corresponding to a slope efficiency of 41% and pulse characteristics of 48 ns/5.5 µJ which are superior to that for graphene-SA (123 ns/3.1 µJ) and SESA (61 ns/1.1 µJ). SWCNT-SAs are promising for eye-safe miniature lasers at ~2 µm generating nanosecond pulses in the MHz repetition frequency range.

  19. Periodic adjustment of the position of a laser beam spot on a semiconductor saturable absorber mirror in a passively mode-locked solid-state laser

    Xia Pa-Keti; Yan Ping; Gong Ma-Li


    A laser diode end-pumped passively mode-locked Nd:YV04 solid-state laser with a semiconductor saturable absorber mirror (SESAM),in which the intracavity laser beam spot on the SESAM can be adjusted periodically,is investigated. Inserting a rectangular prism (RP) into the laser cavity is a promising approach towards the goal of periodically moving the position of the focus spot of the intracavity pulse on the SESAM surface to avoid the long-time irradiation of the laser beam on the same position,thereby solving a series of problems caused by damage to the SESAM and greatly prolonging its usage life. The adjustment of the rectangular prism in the laser cavity does not break the stable continuous wave (CW) mode-locked condition. The laser generates a stable picosecond pulse sequence at 1064 nm with an output power of 3.6 W and a pulse width of 14 ps. The instabilities of the output power and the pulse width are 1.77% and 4.5%,respectively.

  20. Assessment of bioburden encapsulated in bulk materials

    Schubert, Wayne W.; Newlin, Laura; Chung, Shirley Y.; Ellyin, Raymond


    The National Aeronautics and Space Administration (NASA) imposes bioburden limitations on all spacecraft destined for solar system bodies that might harbor evidence of extant or extinct life. The subset of microorganisms trapped within solid materials during manufacture and assembly is referred to as encapsulated bioburden. In the absence of spacecraft-specific data, NASA relies on specification values to estimate total spacecraft encapsulated bioburden, typically 30 endospores/cm3 or 300 viable cells/cm3 in non-electronic materials. Specification values for endospores have been established conservatively, and represent no less than an order of magnitude greater abundance than that derived from empirical assessments of actual spacecraft materials. The goal of this study was to generate data germane to determining whether revised bulk encapsulated material values (lower than those estimated by historical specifications) tailored specifically to the materials designated in modern-day spacecraft design could be used, on a case-by-case basis, to comply with planetary protection requirements. Organic materials having distinctly different chemical properties and configurations were selected. This required more than one experimental and analytical approach. Filtration was employed for liquid electrolytes, lubricants were suspended in an aqueous solution and solids (wire and epoxy sealant) were cryogenically milled. The final data characteristic for all bioburden estimates was microbial colony formation in rich agar growth medium. To assess survival potential, three non-spore-forming bacterial cell lines were systematically encapsulated in an epoxy matrix, liberated via cryogenic grinding, and cultured. Results suggest that bulk solid materials harbor significantly fewer encapsulated microorganisms than are estimated by specification values. Lithium-ion battery electrolyte reagents housed fewer than 1 CFU/cm3. Results also demonstrated that non-spore-forming microorganisms

  1. The coupling of thermochemistry and phase diagrams for group III-V semiconductor systems. Final report

    Anderson, T.J.


    The project was directed at linking the thermochemical properties of III-V compound semiconductors systems with the reported phase diagrams. The solid-liquid phase equilibrium problem was formulated and three approaches to calculating the reduced standard state chemical potential were identified and values were calculated. In addition, thermochemical values for critical properties were measured using solid state electrochemical techniques. These values, along with the standard state chemical potentials and other available thermochemical and phase diagram data, were combined with a critical assessment of selected III-V systems. This work was culminated with a comprehensive assessment of all the III-V binary systems. A novel aspect of the experimental part of this project was the demonstration of the use of a liquid encapsulate to measure component activities by a solid state emf technique in liquid III-V systems that exhibit high vapor pressures at the measurement temperature.

  2. Semiconductor surface protection material

    Packard, R. D. (Inventor)


    A method and a product for protecting semiconductor surfaces is disclosed. The protective coating material is prepared by heating a suitable protective resin with an organic solvent which is solid at room temperature and converting the resulting solution into sheets by a conventional casting operation. Pieces of such sheets of suitable shape and thickness are placed on the semiconductor areas to be coated and heat and vacuum are then applied to melt the sheet and to drive off the solvent and cure the resin. A uniform adherent coating, free of bubbles and other defects, is thus obtained exactly where it is desired.

  3. Spent nuclear fuel rods encapsulated in copper

    Hanes, H.D.


    Using hot isostatic pressing, spent nuclear fuel rods and other radioactive wastes can be encapsulated in solid copper. The copper capsule which is formed is free of pores and cracks, and is highly resistant to attack by reducing ground waters. Such capsules should contain radioactive materials safely for hundreds of thousands of years in underground storage.

  4. Stability of lipid encapsulated ferulic acid particles

    Encapsulation of bioactive compounds by a solid lipid matrix provides stability and a mechanism for controlled release in formulated products. Phenolic compounds exhibit antioxidant and antimicrobial activities and have applications as functional food and feed additives. Ferulic acid, a common pheno...

  5. Sample size requirements for estimating effective dose from computed tomography using solid-state metal-oxide-semiconductor field-effect transistor dosimetry

    Trattner, Sigal; Cheng, Bin; Pieniazek, Radoslaw L.; Hoffmann, Udo; Douglas, Pamela S.; Einstein, Andrew J.


    Purpose: Effective dose (ED) is a widely used metric for comparing ionizing radiation burden between different imaging modalities, scanners, and scan protocols. In computed tomography (CT), ED can be estimated by performing scans on an anthropomorphic phantom in which metal-oxide-semiconductor field-effect transistor (MOSFET) solid-state dosimeters have been placed to enable organ dose measurements. Here a statistical framework is established to determine the sample size (number of scans) needed for estimating ED to a desired precision and confidence, for a particular scanner and scan protocol, subject to practical limitations. Methods: The statistical scheme involves solving equations which minimize the sample size required for estimating ED to desired precision and confidence. It is subject to a constrained variation of the estimated ED and solved using the Lagrange multiplier method. The scheme incorporates measurement variation introduced both by MOSFET calibration, and by variation in MOSFET readings between repeated CT scans. Sample size requirements are illustrated on cardiac, chest, and abdomen–pelvis CT scans performed on a 320-row scanner and chest CT performed on a 16-row scanner. Results: Sample sizes for estimating ED vary considerably between scanners and protocols. Sample size increases as the required precision or confidence is higher and also as the anticipated ED is lower. For example, for a helical chest protocol, for 95% confidence and 5% precision for the ED, 30 measurements are required on the 320-row scanner and 11 on the 16-row scanner when the anticipated ED is 4 mSv; these sample sizes are 5 and 2, respectively, when the anticipated ED is 10 mSv. Conclusions: Applying the suggested scheme, it was found that even at modest sample sizes, it is feasible to estimate ED with high precision and a high degree of confidence. As CT technology develops enabling ED to be lowered, more MOSFET measurements are needed to estimate ED with the same

  6. Encapsulation plant at Forsmark

    Nystroem, Anders


    SKB has already carried out a preliminary study of an encapsulation plant detached from Clab (Central interim storage for spent fuels). This stand-alone encapsulation plant was named FRINK and its assumed siting was the above-ground portion of the final repository, irrespective of the repository's location. The report previously presented was produced in cooperation with BNFL Engineering Ltd in Manchester and the fuel reception technical solution was examined by Gesellschaft fuer Nuklear-Service mbH (GNS) in Hannover and by Societe Generale pour les Techniques Nouvelles (SGN) in Paris. This report is an update of the earlier preliminary study report and is based on the assumption that the encapsulation plant and also the final repository will be sited in the Forsmark area. SKB's main alternative for siting the encapsulation plant is next to Clab. Planning of this facility is ongoing and technical solutions from the planning work have been incorporated in this report. An encapsulation plant placed in proximity to any final repository in Forsmark forms part of the alternative presentation in the application for permission to construct and operate an installation at Clab. The main technical difference between the planned encapsulation plant at Clab and an encapsulation plant at a final repository at Forsmark is how the fuel is managed and prepared before actual encapsulation. Fuel reception at the encapsulation plant in Forsmark would be dry, i.e. there would be no water-filled pools at the facility. Clab is used for verificatory fuel measurements, sorting and drying of the fuel before transport to Forsmark. This means that Clab will require a measure of rebuilding and supplementary equipment. In purely technical terms, the prospects for building an encapsulation plant sited at Forsmark are good. A description of the advantages and drawbacks of siting the encapsulation plant at Clab as opposed to any final repository at Forsmark is presented in a separate

  7. The demise of plastic encapsulated microcircuit myths

    Hakim, E. B.; Agarwal, R. K.; Pecht, M.


    Production of microelectronic devices encapsulated in solid, molded plastic packages has rapidly increased since the early 1980's. Today, millions of plastic-encapsulated devices are produced daily. On the other hand, only a few million hermetic (cavity) packages are produced per year. Reasons for the increased use of plastic-encapsulated packages include cost, availability, size, weight, quality, and reliability. Markets taking advantage of this technology range from computers and telecommunications to automotive uses. Yet, several industries, the military in particular, will not accept such devices. One reason for this reluctance to use the best available commercial parts is a perceived risk of poor reliability, derived from antiquated military specifications, standards, and handbooks; other common justifications cite differing environments; inadequate screens; inadequate test data, and required government audits of suppliers' processes. This paper describes failure mechanisms associated with plastic encapsulation and their elimination. It provides data indicating the relative reliability of cavity and solid-encapsulated packaging, and presents possible approaches to assuring quality and reliability in the procuring and applying this successful commercial technology.

  8. Basic Semiconductor Physics

    Hamaguchi, Chihiro


    This book presents a detailed description of the basic semiconductor physics. The reader is assumed to have a basic command of mathematics and some elementary knowledge of solid state physics. The text covers a wide range of important phenomena in semiconductors, from the simple to the advanced. The reader can understand three different methods of energy band calculations, empirical pseudo-potential, k.p perturbation and tight-binding methods. The effective mass approximation and electron motion in a periodic potential, Boltzmann transport equation and deformation potentials used for full band Monte Carlo simulation are discussed. Experiments and theoretical analysis of cyclotron resonance are discussed in detail because the results are essential to the understanding of semiconductor physics. Optical and transport properties, magneto-transport, two dimensional electron gas transport (HEMT and MOSFET), and quantum transport are reviewed, explaining optical transition, electron phonon interactions, electron mob...

  9. Semiconductor spintronics

    Xia, Jianbai; Chang, Kai


    Semiconductor Spintronics, as an emerging research discipline and an important advanced field in physics, has developed quickly and obtained fruitful results in recent decades. This volume is the first monograph summarizing the physical foundation and the experimental results obtained in this field. With the culmination of the authors' extensive working experiences, this book presents the developing history of semiconductor spintronics, its basic concepts and theories, experimental results, and the prospected future development. This unique book intends to provide a systematic and modern foundation for semiconductor spintronics aimed at researchers, professors, post-doctorates, and graduate students, and to help them master the overall knowledge of spintronics.

  10. Semiconductor heterojunctions

    Sharma, B L


    Semiconductor Heterojunctions investigates various aspects of semiconductor heterojunctions. Topics covered include the theory of heterojunctions and their energy band profiles, electrical and optoelectronic properties, and methods of preparation. A number of heterojunction devices are also considered, from photovoltaic converters to photodiodes, transistors, and injection lasers.Comprised of eight chapters, this volume begins with an overview of the theory of heterojunctions and a discussion on abrupt isotype and anisotype heterojunctions, along with graded heterojunctions. The reader is then

  11. Encapsulation with structured triglycerides

    Lipids provide excellent materials to encapsulate bioactive compounds for food and pharmaceutical applications. Lipids are renewable, biodegradable, and easily modified to provide additional chemical functionality. The use of structured lipids that have been modified with photoactive properties are ...

  12. Semiconductor lasers and herterojunction leds

    Kressel, Henry


    Semiconductor Lasers and Heterojunction LEDs presents an introduction to the subject of semiconductor lasers and heterojunction LEDs. The book reviews relevant basic solid-state and electromagnetic principles; the relevant concepts in solid state physics; and the p-n junctions and heterojunctions. The text also describes stimulated emission and gain; the relevant concepts in electromagnetic field theory; and the modes in laser structures. The relation between electrical and optical properties of laser diodes; epitaxial technology; binary III-V compounds; and diode fabrication are also consider

  13. Optical Properties of Non-Crystalline Semiconductors.


    Instruments, 1974, unpublished. 42. de Neufville, J.P., Photostructural transformations in amorphous solids, 0 in Optical Properties of Solids --New...semiconductors, in Optical Properties of Solids , Nudelman, S., and Mitra, S.S., eds., Plenum, N.Y., 1969, 123. 52. Cody, G.D., Brooks, B.G., and

  14. Solubility, photostability and antifungal activity of phenylpropanoids encapsulated in cyclodextrins.

    Kfoury, Miriana; Lounès-Hadj Sahraoui, Anissa; Bourdon, Natacha; Laruelle, Frédéric; Fontaine, Joël; Auezova, Lizette; Greige-Gerges, Hélène; Fourmentin, Sophie


    Effects of the encapsulation in cyclodextrins (CDs) on the solubility, photostability and antifungal activities of some phenylpropanoids (PPs) were investigated. Solubility experiments were carried out to evaluate the effect of CDs on PPs aqueous solubility. Loading capacities and encapsulation efficiencies of freeze-dried inclusion complexes were determined. Moreover, photostability assays for both inclusion complexes in solution and solid state were performed. Finally, two of the most widespread phytopathogenic fungi, Fusarium oxysporum and Botrytis cinerea, were chosen to examine the antifungal activity of free and encapsulated PPs. Results showed that encapsulation in CDs significantly increased the solubility and photostability of studied PPs (by 2 to 17-fold and 2 to 44-fold, respectively). Free PPs revealed remarkable antifungal properties with isoeugenol showing the lowest half-maximal inhibitory concentration (IC50) values of mycelium growth and spore germination inhibition. Encapsulated PPs, despite their reduced antifungal activity, could be helpful to solve drawbacks such as solubility and stability.

  15. Energetics of the Semiconductor-Electrolyte Interface.

    Turner, John A.


    The use of semiconductors as electrodes for electrochemistry requires an understanding of both solid-state physics and electrochemistry, since phenomena associated with both disciplines are seen in semiconductor/electrolyte systems. The interfacial energetics of these systems are discussed. (JN)

  16. Oxide semiconductors

    Svensson, Bengt G; Jagadish, Chennupati


    Semiconductors and Semimetals has distinguished itself through the careful selection of well-known authors, editors, and contributors. Originally widely known as the ""Willardson and Beer"" Series, it has succeeded in publishing numerous landmark volumes and chapters. The series publishes timely, highly relevant volumes intended for long-term impact and reflecting the truly interdisciplinary nature of the field. The volumes in Semiconductors and Semimetals have been and will continue to be of great interest to physicists, chemists, materials scientists, and device engineers in academia, scient

  17. Polymer semiconductor crystals

    Jung Ah Lim


    Full Text Available One of the long-standing challenges in the field of polymer semiconductors is to figure out how long interpenetrating and entangled polymer chains self-assemble into single crystals from the solution phase or melt. The ability to produce these crystalline solids has fascinated scientists from a broad range of backgrounds including physicists, chemists, and engineers. Scientists are still on the hunt for determining the mechanism of crystallization in these information-rich materials. Understanding the theory and concept of crystallization of polymer semiconductors will undoubtedly transform this area from an art to an area that will host a bandwagon of scientists and engineers. In this article we describe the basic concept of crystallization and highlight some of the advances in polymer crystallization from crystals to nanocrystalline fibers.

  18. Compound semiconductor device modelling

    Miles, Robert


    Compound semiconductor devices form the foundation of solid-state microwave and optoelectronic technologies used in many modern communication systems. In common with their low frequency counterparts, these devices are often represented using equivalent circuit models, but it is often necessary to resort to physical models in order to gain insight into the detailed operation of compound semiconductor devices. Many of the earliest physical models were indeed developed to understand the 'unusual' phenomena which occur at high frequencies. Such was the case with the Gunn and IMPATI diodes, which led to an increased interest in using numerical simulation methods. Contemporary devices often have feature sizes so small that they no longer operate within the familiar traditional framework, and hot electron or even quantum­ mechanical models are required. The need for accurate and efficient models suitable for computer aided design has increased with the demand for a wider range of integrated devices for operation at...

  19. Semiconductor physics an introduction

    Seeger, Karlheinz


    Semiconductor Physics - An Introduction - is suitable for the senior undergraduate or new graduate student majoring in electrical engineering or physics. It will also be useful to solid-state scientists and device engineers involved in semiconductor design and technology. The text provides a lucid account of charge transport, energy transport and optical processes, and a detailed description of many devices. It includes sections on superlattices and quantum well structures, the effects of deep-level impurities on transport, the quantum Hall effect and the calculation of the influence of a magnetic field on the carrier distribution function. This 6th edition has been revised and corrected, and new sections have been added to different chapters.

  20. Broadband fast semiconductor saturable absorber.

    Jacobovitz-Veselka, G R; Kellerm, U; Asom, T


    Kerr lens mode-locked (KLM) solid-state lasers are typically not self-starting. We address this problem by introducing a broadband semiconductor saturable absorber that could be used as a tunable, all-solid-state, passive starting mechanism. We extend the wavelength tunability of a semiconductor saturable absorber to more than 100 nm using a band-gap-engineered low-temperature molecular-beam-epitaxy (MBE)-grown bulk AlGaAs semiconductor saturable absorber in which the absorption edge of the saturable absorber has been artificially broadened by continuously reducing the Al concentration during the MBE growth. We demonstrate its tunability and its feasibility as a starting mechanism for KLM with a picosecond resonant passive mode-locked Ti:sapphire laser. The extension to femtosecond KLM lasers has been discussed previously.

  1. Silica Micro Encapsulation

    Mitchell, P.; Whitbread-Jordan, M. [KEECO (United Kingdom)


    The article explains how Silica Micro Encapsulation (SME) water treatment technology may be transferred from metal mining to coal mining operations. KEECO has been developing a unique solution for treating acid rock drainage in the metal sulphide mining sector and following trials in metal mining operations (described in the article), is preparing to transfer the technology to the coal industry. SME technology comprises metal precipitation and encapsulation accomplished with proprietary chemical, KB-1, and a group of patented chemical dosing systems, the K-series, to dose KB-1 into contaminated liquid wastes as a dry powder. 4 figs., 4 tabs.

  2. Subcutaneous encapsulated fat necrosis

    Aydin, Dogu; Berg, Jais O


    We have described subcutaneous encapsulated fat necrosis, which is benign, usually asymptomatic and underreported. Images have only been published on two earlier occasions, in which the necrotic nodules appear "pearly" than the cloudy yellow surface in present case. The presented image may help f...... future surgeons to establish the diagnosis peroperatively....

  3. Semiconductor Detectors; Detectores de Semiconductores

    Cortina, E.


    Particle detectors based on semiconductor materials are among the few devices used for particle detection that are available to the public at large. In fact we are surrounded by them in our daily lives: they are used in photoelectric cells for opening doors, in digital photographic and video camera, and in bar code readers at supermarket cash registers. (Author)

  4. Electrodeposited polymer encapsulated nickel sulphide thin films: frequency switching material

    Jana, Sumanta, E-mail: [Department of Chemistry, Bengal Engineering and Science University, Botanic Garden, Howrah 711103, WB (India); Mukherjee, Nillohit [Centre of Excellence for Green Energy and Sensor Systems, Bengal Engineering and Science University, Howrah 711103, WB (India); Chakraborty, Biswajit [Department of Chemistry, Vivekananda Mahavidyalay, Burdwan 713103, WB (India); Mitra, Bibhas Chandra [Department of Physics, Bengal Engineering and Science University, Botanic Garden, Howrah 711103, WB (India); Mondal, Anup, E-mail: [Department of Chemistry, Bengal Engineering and Science University, Botanic Garden, Howrah 711103, WB (India)


    Graphical abstract: Polyvinylpyrrolidone encapsulated NiS thin films were synthesized electrochemically. The light induced frequency switching study of the synthesized material was carried out and it was observed that the films performed well as a switching device under 1 Sun illumination. This pulse generation within an insulating polymer encapsulated semicondctor matrix (PVP NiS) might be due to surface covering which leads to reduction of recombination process. Highlights: • PVP-NiS thin films were electrochemically synthesized. • Encapsulation of PVP causes surface modification of NiS by reducing surface states. • The synthesized thin films were used as frequency switching material which generates ~ 50 Hz frequency under 1 Sun irradiation. Abstract: Polyvinylpyrrolidone (PVP) encapsulated nickel sulfide (NiS) thin films have been synthesized electrochemically from aqueous solution of hydrated nickel chloride (NiCl₂, 6H₂O), thioacetamide (CH₃C(S) NH₂) (TAA) and polyvinylpyrrolidone (PVP). Surface modification of nickel sulfide (NiS) thin films was achieved by this polymer encapsulation. X-ray diffraction (XRD), high resolution transmission electron microscope (HRTEM), field emission scanning electron microscopy (FESEM) and Energy dispersive X-radiation (EDAX) techniques were used for the characterization of thin films. Infrared spectroscopy (IR) confirmed the formation of polymer encapsulated semiconductor. Frequency switching generation study shows that the encapsulated material could be used as a frequency switching device that generates a frequency ~ 50 Hz under 1 Sun illumination. Encapsulation with PVP causes surface modification that reduces the surface states and barrier height. As a result, the width of the depletion region decreases. So the number of electron-hole pairs increases. Consequently, the number of excitons and exciton related emission increases and this leads to reduction of recombination process and shows photo induced

  5. Semiconductor Optics

    Klingshirn, Claus F


    This updated and enlarged new edition of Semiconductor Optics provides an introduction to and an overview of semiconductor optics from the IR through the visible to the UV, including linear and nonlinear optical properties, dynamics, magneto and electrooptics, high-excitation effects and laser processes, some applications, experimental techniques and group theory. The mathematics is kept as elementary as possible, sufficient for an intuitive understanding of the experimental results and techniques treated. The subjects covered extend from physics to materials science and optoelectronics. Significantly updated chapters add coverage of current topics such as electron hole plasma, Bose condensation of excitons and meta materials. Over 120 problems, chapter introductions and a detailed index make it the key textbook for graduate students in physics. The mathematics is kept as elementary as possible, sufficient for an intuitive understanding of the experimental results and techniques treated. The subjects covered ...

  6. Semiconductor sensors

    Hartmann, Frank, E-mail: frank.hartmann@cern.c [Institut fuer Experimentelle Kernphysik, KIT, Wolfgang-Gaede-Str. 1, Karlsruhe 76131 (Germany)


    Semiconductor sensors have been around since the 1950s and today, every high energy physics experiment has one in its repertoire. In Lepton as well as Hadron colliders, silicon vertex and tracking detectors led to the most amazing physics and will continue doing so in the future. This contribution tries to depict the history of these devices exemplarily without being able to honor all important developments and installations. The current understanding of radiation damage mechanisms and recent R and D topics demonstrating the future challenges and possible technical solutions for the SLHC detectors are presented. Consequently semiconductor sensor candidates for an LHC upgrade and a future linear collider are also briefly introduced. The work presented here is a collage of the work of many individual silicon experts spread over several collaborations across the world.

  7. Survey of semiconductor physics

    Böer, Karl W


    Any book that covers a large variety of subjects and is written by one author lacks by necessity the depth provided by an expert in his or her own field of specialization. This book is no exception. It has been written with the encouragement of my students and colleagues, who felt that an extensive card file I had accumulated over the years of teaching solid state and semiconductor physics would be helpful to more than just a few of us. This file, updated from time to time, contained lecture notes and other entries that were useful in my research and permitted me to give to my students a broader spectrum of information than is available in typical textbooks. When assembling this material into a book, I divided the top­ ics into material dealing with the homogeneous semiconductor, the subject of the previously published Volume 1, and the inhomoge­ neous semiconductor, the subject of this Volume 2. In order to keep the book to a manageable size, sections of tutorial character which can be used as text for a g...

  8. Production of organic-semiconductor nanostructures by solid-phase wetting. Guided growth, molecular data storage, and local coadsorption; Erzeugung organischer Halbleiter-Nanostrukturen durch Festphasenbenetzung. Gefuehrtes Wachstum, molekulare Datenspeicherung und lokale Koadsorption

    Trixler, Frank


    The present thesis treats questions from the interdisciplinary field of nanosciences by studies by means of scanning tunneling microscopy and computer chemistry. The main part of this thesis is the presentation of a novel structure formation process on molecular level. The presented model describes this process by nanocrystals, which show - suspended in a matrix - in contact with a crystal surface a behaviour, which is in spite present solid-state properties (crystalline order) similar to the behaviour of liquid drops in the wetting of surfaces. Starting from this the technological potential of this new process is made accessible.: 1.) Adsorbate structures of a series of organic semiconductors are described for the first time. By this it is additionally shown that by supramolecular solid-phase wetting unsolvable semiconductor molecules can be very simply and under environmental conditions orderedly adsorbed. 2.) An explanation model is developed, by which the hitherto not understandable molecular data storage by means of PTCDA molecules can be theoretically explained and extended to further molecules. 3.) The development of a nanofabrication concept is presented, which allows a local control of the growth of nanostructures. The advance against a classical molecule-for-molecule performed nanostructuration lies therein that by the tip of a scanning tunneling microscope solely the information of growth directions is locally to be brought into the system, the actual formation of the structures however takes place by independently running and by this qualitatively and timely highly efficient growth processes. 4.) A procedure is presented, which allows a local adsorption of molecules to ordered layers within a layer of other molecules and by this makes possible the formation of heterogeneous adsorbate layers.

  9. Bonds and bands in semiconductors

    Phillips, Jim


    This classic work on the basic chemistry and solid state physics of semiconducting materials is now updated and improved with new chapters on crystalline and amorphous semiconductors. Written by two of the world's pioneering materials scientists in the development of semiconductors, this work offers in a single-volume an authoritative treatment for the learning and understanding of what makes perhaps the world's most important engineered materials actually work. Readers will find: --' The essential principles of chemical bonding, electron energy bands and their relationship to conductive and s

  10. Encapsulation of Liquids Via Extrusion--A Review.

    Tackenberg, Markus W; Kleinebudde, Peter


    Various encapsulation techniques are known for pharmaceutical applications. Extrusion is of minor importance. However, extrusion is used to obtain granules with encapsulate liquid active ingredients (AI) like essential oils and flavours for food applications since decades. Many of these AIs can be used for agrochemical, home care, and pharmaceutical products, too. Thus, the focus of this review is on the interdisciplinary presentation and evaluation of the available knowledge about the encapsulation process via extrusion. The desired microcapsule structure is discussed at the outset. The microcapsule is compared to the alternative glassy solid solution system, before an overview of suitable excipients is given. In the next section the development of the extrusion technique, used for encapsulation processes, is presented. Thereby, the focus is on encapsulation using twin-screw extruders. Additionally, the influence of the downstream processes on the products is discussed, too. The understanding of the physical processes during extrusion is essential for specifically adjustment of the desired product properties and thus, highlighted in this paper. Unfortunately not all processes, especially the mixing process, are well studied. Suggestions for further studies, to improve process understanding and product quality, are given, too. The last part of this review focuses on the characterization of the obtained granules, especially AI content, encapsulation efficiency, and storage stability. In conclusion, extrusion is a standard technique for flavour encapsulation, but future studies, may lead to more (pharmaceutical) applications and new products.

  11. Design documentation: Krypton encapsulation preconceptual design

    Knecht, D.A. [Idaho National Engineering Lab., Idaho Falls, ID (United States)


    US EPA regulations limit the release of Krypton-85 to the environment from commercial facilities after January 1, 1983. In order to comply with these regulations, Krypton-85, which would be released during reprocessing of commercial nuclear fuel, must be collected and stored. Technology currently exists for separation of krypton from other inert gases, and for its storage as a compressed gas in steel cylinders. The requirements, which would be imposed for 100-year storage of Krypton-85, have led to development of processes for encapsulation of krypton within a stable solid matrix. The objective of this effort was to provide preconceptual engineering designs, technical evaluations, and life cycle costing data for comparison of two alternate candidate processes for encapsulation of Krypton-85. This report has been prepared by The Ralph M. Parsons Company for the US Department of Energy.

  12. Study on preparation of β-cyclodextrin encapsulation tea extract.

    Haidong, Liang; Fang, Yu; Zhihong, Tong; Changle, Ren


    Microencapsulation of ethanol extract of tea was performed in this study. In order to microencapsulate, β-cyclodextrin was used as wall material. Ethanol extract of tea was used as the core material. Microcapsules in the solid form were obtained by drying the emulsions. RSM showed that optimal processing parameters were as followings: core material/wall material 1/4, β-cyclodextrin content 16%, stirring time 30 min and stirring temperature 200°C. Pharmacological activities of β-cyclodextrin encapsulation tea extract were determined. It was found that β-cyclodextrin encapsulation tea extract could enhance BMD, BMC and bone Ca, Zn and Cu contents. In addition, β-cyclodextrin encapsulation tea extract could still reduce blood Ca contents. These results indicated that β-cyclodextrin encapsulation tea extract was useful for improving bone quality in aged animals.

  13. Determination of Loureirin A in Solid Lipid Nanoparticles Encapsulating Resina Draconis by HPLC%HPLC测定龙血竭脂质纳米粒中龙血素A的含量

    叶菲; 楼雪芳; 杜永忠


    目的 采用HPLC测定龙血竭脂质纳米粒中龙血素A的含量并计算其包封率.方法 采用DiamonsilTM C18(200mm×4.6mm,5μm)色谱柱,以乙腈-1%冰醋酸水溶液(38:62)为流动相,流速为1.3 mL·min-1,检测波长为260 nm,柱温为40℃,测定样品中龙血素A的含量并计算其包封率.结果 龙血素A于0.135~5.4μg·mL-1内有良好线性关系,Y=33.694X+1.5898(r=0.999 9).低、中、高3个浓度的日内RSD分别为2.70%,2.36%,1.48%;日间RSD分别为2.70%,2.61%,1.97%,该方法的平均回收率为99.2%,RSD为3.9%,平均包封率为89.59%.结论 本方法准确、简便、重复性好,可用于龙血竭脂质纳米粒中龙血素A含量的测定.%OBJECTIVE To establish an HPLC method for determination of loureirin A content in solid lipid nanoparticles(SLN) of Resina Draconis. METHODS A DiamonsilTM C18(200 mm×4.6 mm, 5 μm) column was used for the determination of loureirin A with mobile phase of acetonitrile-1% acetic acid solution (38 : 62). The flow rate was 1.3 mL·min-1, the detection wavelength was set at 260 nm, and the column temperature was 40℃. RESULTS The linear range of loureirin A was 0.135-5.4 μg·mL-1, Y=33.694X+1.589 8(r=0.999 9). The RSDs of within-day were 2.70%, 2.36%, 1.48%, and the RSDs of between-day were 2.70%, 2.61%, 1.97% in the high-, middle-, and low-dose Resina Draconis loaded SLN. The average recovery was 99.2%(RSD 3.9%), and the average drug encapsulation efficiency was 89.59%. CONCLUSION The method is simple and reliable for the determination of loureirin A in Resina Draconis loaded SLN.

  14. Semiconductor laser

    Ito, K.; Shyuue, M.


    A distributed feedback semiconductor laser is proposed which generates several beams with equal wavelengths in different directions. For this purpose, 1 millimeter grooves are cut into the surface of an n-type conductance GaAs plate in three different directions; these grooves form a diffraction grating. The center of this plate has no grooves and is bombarded by an He/Ne laser beam. The diffraction gratings provide resonance properties and generate laser beams with wavelengths of 8850, 9000 and 9200 angstroms.

  15. The Physics of Semiconductors An Introduction Including Nanophysics and Applications

    Grundmann, Marius


    The Physics of Semiconductors contains ample material for a comprehensive upper-level undergraduate or beginning graduate course, guiding readers to the point where they can choose a special topic and begin supervised research. The textbook provides a balance between essential aspects of solid-state and semiconductor physics, on the one hand, and the principles of various semiconductor devices and their applications in electronic and photonic devices, on the other. It highlights many practical aspects of semiconductors such as alloys, strain, heterostructures, nanostructures, that are necessary in modern semiconductor research but typically omitted in textbooks. Coverage also includes additional advanced topics, such as Bragg mirrors, resonators, polarized and magnetic semiconductors. The text derives explicit formulas for many results to support better understanding of the topics. The Physics of Semiconductors requires little or no prior knowledge of solid-state physics and evolved from a highly regarded two...

  16. The Physics of Semiconductors An Introduction Including Devices and Nanophysics

    Grundmann, Marius


    The Physics of Semiconductors provides material for a comprehensive upper-level-undergrauate and graduate course on the subject, guiding readers to the point where they can choose a special topic and begin supervised research. The textbook provides a balance between essential aspects of solid-state and semiconductor physics, on the one hand, and the principles of various semiconductor devices and their applications in electronic and photonic devices, on the other. It highlights many practical aspects of semiconductors such as alloys, strain, heterostructures, nanostructures, that are necessary in modern semiconductor research but typically omitted in textbooks. For the interested reader some additional advanced topics are included, such as Bragg mirrors, resonators, polarized and magnetic semiconductors are included. Also supplied are explicit formulas for many results, to support better understanding. The Physics of Semiconductors requires little or no prior knowledge of solid-state physics and evolved from ...

  17. Wafer-fused semiconductor radiation detector

    Lee, Edwin Y.; James, Ralph B.


    Wafer-fused semiconductor radiation detector useful for gamma-ray and x-ray spectrometers and imaging systems. The detector is fabricated using wafer fusion to insert an electrically conductive grid, typically comprising a metal, between two solid semiconductor pieces, one having a cathode (negative electrode) and the other having an anode (positive electrode). The wafer fused semiconductor radiation detector functions like the commonly used Frisch grid radiation detector, in which an electrically conductive grid is inserted in high vacuum between the cathode and the anode. The wafer-fused semiconductor radiation detector can be fabricated using the same or two different semiconductor materials of different sizes and of the same or different thicknesses; and it may utilize a wide range of metals, or other electrically conducting materials, to form the grid, to optimize the detector performance, without being constrained by structural dissimilarity of the individual parts. The wafer-fused detector is basically formed, for example, by etching spaced grooves across one end of one of two pieces of semiconductor materials, partially filling the grooves with a selected electrical conductor which forms a grid electrode, and then fusing the grooved end of the one semiconductor piece to an end of the other semiconductor piece with a cathode and an anode being formed on opposite ends of the semiconductor pieces.

  18. Magnetic semiconductors

    Bihler, Christoph


    In this thesis we investigated in detail the properties of Ga{sub 1-x}Mn{sub x}As, Ga{sub 1-x}Mn{sub x}P, and Ga{sub 1-x}Mn{sub x}N dilute magnetic semiconductor thin films with a focus on the magnetic anisotropy and the changes of their properties upon hydrogenation. We applied two complementary spectroscopic techniques to address the position of H in magnetic semiconductors: (i) Electron paramagnetic resonance, which provides direct information on the symmetry of the crystal field of the Mn{sup 2+} atoms and (ii) x-ray absorption fine structure analysis which allows to probe the local crystallographic neighborhood of the absorbing Mn atom via analysing the fine structure at the Mn K absorption edge. Finally, we discussed the obstacles that have to be overcome to achieve Curie temperatures above the current maximum in Ga{sub 1-x}Mn{sub x}As of 185 K. Here, we outlined in detail the generic problem of the formation of precipitates at the example of Ge:MN. (orig.)

  19. Semiconductor Laser Measurements Laboratory

    Federal Laboratory Consortium — The Semiconductor Laser Measurements Laboratory is equipped to investigate and characterize the lasing properties of semiconductor diode lasers. Lasing features such...

  20. Encapsulation of graphene in Parylene

    Skoblin, Grigory; Sun, Jie; Yurgens, August


    Graphene encapsulated between flakes of hexagonal boron nitride (hBN) demonstrates the highest known mobility of charge carriers. However, the technology is not scalable to allow for arrays of devices. We are testing a potentially scalable technology for encapsulating graphene where we replace hBN with Parylene while still being able to make low-ohmic edge contacts. The resulting encapsulated devices show low parasitic doping and a robust Quantum Hall effect in relatively low magnetic fields <5 T.

  1. Molecular engineering of semiconductor surfaces and devices.

    Ashkenasy, Gonen; Cahen, David; Cohen, Rami; Shanzer, Abraham; Vilan, Ayelet


    Grafting organic molecules onto solid surfaces can transfer molecular properties to the solid. We describe how modifications of semiconductor or metal surfaces by molecules with systematically varying properties can lead to corresponding trends in the (electronic) properties of the resulting hybrid (molecule + solid) materials and devices made with them. Examples include molecule-controlled diodes and sensors, where the electrons need not to go through the molecules (action at a distance), suggesting a new approach to molecule-based electronics.

  2. Water encapsulation in a polyoxapolyaza macrobicyclic compound.

    Mateus, Pedro; Delgado, Rita; Groves, Patrick; Campos, Sara R R; Baptista, António M; Brandão, Paula; Félix, Vítor


    A new heteroditopic macrobicyclic compound (t(2)pN(5)O(3)) containing two separate polyoxa and polyaza compartments was synthesized in good yield through a [1 + 1] "tripod-tripod coupling" strategy. The X-ray crystal structure of H(3)t(2)pN(5)O(3)(3+) revealed the presence of one encapsulated water molecule accepting two hydrogen bonds from two protonated secondary amines and donating a hydrogen bond to one amino group. The acid-base behavior of the compound was studied by potentiometry at 298.2 K in aqueous solution and at ionic strength 0.10 M in KCl. The results revealed unusual protonation behavior, namely a surprisingly low fourth protonation constant contrary to what was expected for the compound. (1)H NMR and DOSY experiments, as well as molecular modeling studies, showed that the water encapsulation and the conformation observed in the solid state are retained in solution. The strong binding of the encapsulated water molecule, reinforced by the cooperative occurrence of a trifurcated hydrogen bond at the polyether compartment of the macrobicycle, account for the very low log K(4)(H) value obtained.

  3. Laser cooling of solids

    Epstein, Richard I [Los Alamos National Laboratory; Sheik-bahae, Mansoor [UNM


    We present an overview of solid-state optical refrigeration also known as laser cooling in solids by fluorescence upconversion. The idea of cooling a solid-state optical material by simply shining a laser beam onto it may sound counter intuitive but is rapidly becoming a promising technology for future cryocooler. We chart the evolution of this science in rare-earth doped solids and semiconductors.

  4. Congenital peritoneal encapsulation

    Diana; Teixeira; Vítor; Costa; Paula; Costa; Carlos; Alpoim; Pinto; Correia


    Peritoneal encapsulation(PE) is a rare congenital malformation, characterized by a thin accessory peritoneal membrane which covers all or part of the small bowel, forming an accessory peritoneal sac. Most cases areasymptomatic and diagnosed incidentally during surgery and/or autopsy. Clinical presentation with intestinal obstruction is extremely rare and we report a case. A 25-year-old male, referred to emergency department with diffuse abdominal pain, crampy, with 8 h evolution, associated with nausea, vomiting and constipation in the last 48 h. The abdominal examination revealed an asymmetric and fixed distension, with hard consistency on palpation of lower abdominal quadrants. The abdominal radiography reveals a small bowel distension and fluid levels. Submitted to laparoscopic surgery that recourse to conversion because there is a total peritoneal encapsulation of the small bowel. After opening the peritoneal sac, we find a rotation of mesentery, at its root, conditioning twisting of small bowel and consequently occlusion. Uneventful postoperative with discharged at the 6th day. The PE is a very rare congenital anomaly characterized by abnormal bowel back into the abdominal cavity in the early stages of development. Your knowledge becomes important because, although rare, it might be diagnosis in patients with intestinal obstruction, in the absence of other etiologic factors.

  5. Semiconductor Nanostructures Quantum States and Electronic Transport

    Ihn, Thomas


    This textbook describes the physics of semiconductor nanostructures with emphasis on their electronic transport properties. At its heart are five fundamental transport phenomena: quantized conductance, tunnelling transport, the Aharonov-Bohm effect, the quantum Hall effect, and the Coulomb blockade effect. The book starts out with the basics of solid state and semiconductor physics, such as crystal structure, band structure, and effective mass approximation, including spin-orbit interaction effects important for research in semiconductor spintronics. It contains material aspects such as band e

  6. A study on polypropylene encapsulation and solidification of textile sludge.

    Kumari, V Krishna; Kanmani, S


    The textile sludge is an inevitable solid waste from the textile wastewater process and is categorised under toxic substances by statutory authorities. In this study, an attempt has been made to encapsulate and solidify heavy metals and dyes present in textile sludge using polypropylene and Portland cement. Sludge samples (2 Nos.) were characterized for pH (8.5, 9.5), moisture content (1.5%, 1.96%) and chlorides (245mg/L, 425.4mg/L). Sludge samples were encapsulated into polypropylene with calcium carbonate (additive) and solidified with cement at four different proportions (20, 30, 40, 50%) of sludge. Encapsulated and solidified cubes were made and then tested for compressive strength. Maximum compressive strength of cubes (size, 7.06cm) containing sludge (50%) for encapsulation (16.72 N/mm2) and solidification (18.84 N/mm2) was more than that of standard M15 mortar cubes. The leachability of copper, nickel and chromium has been effectively reduced from 0.58 mg/L, 0.53 mg/L and 0.07 mg/L to 0.28mg/L, 0.26mg/L and BDL respectively in encapsulated products and to 0.24mg/L, BDL and BDL respectively in solidified products. This study has shown that the solidification process is slightly more effective than encapsulation process. Both the products were recommended for use in the construction of non-load bearing walls.

  7. Hydrophobic encapsulation of hydrocarbon gases.

    Leontiev, Alexander V; Saleh, Anas W; Rudkevich, Dmitry M


    [reaction: see text] Encapsulation data for hydrophobic hydrocarbon gases within a water-soluble hemicarcerand in aqueous solution are reported. It is concluded that hydrophobic interactions serve as the primary driving force for the encapsulation, which can be used for the design of gas-separating polymers with intrinsic inner cavities.

  8. High-performance encapsulation in Casanova 2

    Abbadi, Mohamed; Di Giacomo, Francesco; Cortesi, Agostino; Spronck, Pieter; Constantini, Giulia; Maggiore, G.


    Encapsulation is a programming technique that helps developers keeping code readable and maintainable. However, encapsulation in modern object oriented languages often causes significant runtime overhead. Developers must choose between clean encapsulated code or fast code. In the application domain

  9. Semiconductor laser. Halbleiterlaser

    Wuenstel, K.; Gohla, B.; Tegude, F.; Luz, G.; Hildebrand, O.


    A highly modulable semiconductor laser and a process for its manufacture are described. The semiconductor laser has a substrate, a stack of semiconductor layers and electrical contacts. To reduce the capacity, the width of the stack of semiconductor layers is reduced at the sides by anisotropic etching. The electrical contacts are situated on the same side of the substrate and are applied in the same stage of the process. The semiconductor laser is suitable for monolithic integration in other components.

  10. Palisaded encapsulated neuroma

    Adesh S Manchanda


    Full Text Available Palisaded encapsulated neuroma (PEN is a benign cutaneous or mucosal neural tumor which, usually, presents as a solitary, firm, asymptomatic, papule or nodule showing striking predilection for the face. It occurs commonly in middle age, and there is no sex predilection. Oral PEN are not common, and these lesions must be distinguished from other peripheral nerve sheath tumors such as the neurofibroma, neurilemma (schwannoma, and traumatic neuroma. The major challenge in dealing with lesions of PEN is to avoid the misdiagnosis of neural tumors that may be associated with systemic syndromes such as neurofibromatosis and multiple endocrine neoplasia syndrome type 2B. Here, we present a case of benign PEN of the gingiva in the left anterior mandibular region, laying importance on immunohistochemical staining in diagnosing such lesions.

  11. Encapsulation of Aroma

    Zuidam, Nicolaas Jan; Heinrich, Emmanuel

    Flavor is one of the most important characteristics of a food product, since people prefer to eat only food products with an attractive flavor (Voilley and Etiévant 2006). Flavor can be defined as a combination of taste, smell and/or trigeminal stimuli. Taste is divided into five basic ones, i.e. sour, salty, sweet, bitter and umami. Components that trigger the so-called gustatory receptors for these tastes are in general not volatile, in contrast to aroma. Aroma molecules are those that interact with the olfactory receptors in the nose cavity (Firestein 2001). Confusingly, aroma is often referred to as flavor. Trigeminal stimuli cause sensations like cold, touch, and prickling. The current chapter only focuses on the encapsulation of the aroma molecules.

  12. Sclerosing encapsulating peritonitis

    Jen-Jung Pan


    Full Text Available Sclerosing encapsulating peritonitis (SEP is a rare cause of intestinal obstruction. This entity has been reported as either primary idiopathic or secondary to other diseases. We report SEP in 2 cirrhotic patients and review the literature. Both patients had decompensated cirrhosis and episodes of spontaneous bacterial peritonitis. One patient underwent a Denver shunt placement before developing SEP. This patient remains alive and is managed conservatively. The other patient deceased from multi-organ failure after the resection of gangrened small bowel. The manifestations of SEP are often nonspecific that leads to misdiagnosis and/or delayed diagnosis. Early diagnosis of SEP is difficult but not impossible. Surgical treatment is often required when intestinal obstruction is present. Nevertheless, patients with this problem can be treated conservatively with immunosuppressive therapy with or without total parenteral nutrition (TPN before going for surgery.

  13. Mechanically invisible encapsulations

    Mazurek, Piotr Stanislaw

    the commercialisation of such devices. Therefore, this project was dedicated to exploring the possibility of using polar liquids as high dielectric constant fillers for dielectric PDMS-based elastomers. Incorporating polar liquids in the form of discrete droplets into nonpolar membrane swas expected to produce a two......-fold improvement with respect to a reference material. Firstly, dielectric constant enhancement and, secondly, a Young’s modulus decrease were anticipated. In the first approach a flow-focusing microfluidic technique was employed, in order to encapsulate polar liquids within a soft elastomeric shell. The produced...... core-shell microspheres served as a carrier for liquids, enabling the uniform dispersion of the filler droplets within PDMS prepolymer. The dielectric constant of the prepared water-PDMS composite was proven to be enhanced by 30% following the incorporation of 4.5 wt.% of water. Due to the favourable...

  14. Tris(2-(1H-pyrazol-1-yl)pyridine)cobalt(III) as p-type dopant for organic semiconductors and its application in highly efficient solid-state dye-sensitized solar cells.

    Burschka, Julian; Dualeh, Amalie; Kessler, Florian; Baranoff, Etienne; Cevey-Ha, Ngoc-Lê; Yi, Chenyi; Nazeeruddin, Mohammad K; Grätzel, Michael


    Chemical doping is an important strategy to alter the charge-transport properties of both molecular and polymeric organic semiconductors that find widespread application in organic electronic devices. We report on the use of a new class of Co(III) complexes as p-type dopants for triarylamine-based hole conductors such as spiro-MeOTAD and their application in solid-state dye-sensitized solar cells (ssDSCs). We show that the proposed compounds fulfill the requirements for this application and that the discussed strategy is promising for tuning the conductivity of spiro-MeOTAD in ssDSCs, without having to rely on the commonly employed photo-doping. By using a recently developed high molar extinction coefficient organic D-π-A sensitizer and p-doped spiro-MeOTAD as hole conductor, we achieved a record power conversion efficiency of 7.2%, measured under standard solar conditions (AM1.5G, 100 mW cm(-2)). We expect these promising new dopants to find widespread applications in organic electronics in general and photovoltaics in particular.

  15. Tris(2-(1 H -pyrazol-1-yl)pyridine)cobalt(III) as p-Type Dopant for Organic Semiconductors and Its Application in Highly Efficient Solid-State Dye-Sensitized Solar Cells

    Burschka, Julian


    Chemical doping is an important strategy to alter the charge-transport properties of both molecular and polymeric organic semiconductors that find widespread application in organic electronic devices. We report on the use of a new class of Co(III) complexes as p-type dopants for triarylamine-based hole conductors such as spiro-MeOTAD and their application in solid-state dye-sensitized solar cells (ssDSCs). We show that the proposed compounds fulfill the requirements for this application and that the discussed strategy is promising for tuning the conductivity of spiro-MeOTAD in ssDSCs, without having to rely on the commonly employed photo-doping. By using a recently developed high molar extinction coefficient organic D-π-A sensitizer and p-doped spiro-MeOTAD as hole conductor, we achieved a record power conversion efficiency of 7.2%, measured under standard solar conditions (AM1.5G, 100 mW cm -2). We expect these promising new dopants to find widespread applications in organic electronics in general and photovoltaics in particular. © 2011 American Chemical Society.

  16. Singly-resonant sum frequency generation of visible light in a semiconductor disk laser

    Andersen, Martin Thalbitzer; Schlosser, P.J.; Hastie, J.E.;


    In this paper a generic approach for visible light generation is presented. It is based on sum frequency generation between a semiconductor disk laser and a solid-state laser, where the frequency mixing is achieved within the cavity of the semiconductor disk laser using a singlepass of the solid-...... spectrum, by appropriate choice of semiconductor material and single-pass laser wavelength.......In this paper a generic approach for visible light generation is presented. It is based on sum frequency generation between a semiconductor disk laser and a solid-state laser, where the frequency mixing is achieved within the cavity of the semiconductor disk laser using a singlepass of the solid......-state laser light. This exploits the good beam quality and high intra-cavity power present in the semiconductor disk laser to achieve high conversion efficiency. Combining sum frequency mixing and semiconductor disk lasers in this manner allows in principle for generation of any wavelength within the visible...

  17. Encapsulation of shiitake (Lenthinus edodes) flavors by spray drying.

    Shiga, Hirokazu; Yoshii, Hidefumi; Ohe, Hisashi; Yasuda, Masahumi; Furuta, Takeshi; Kuwahara, Hiroshige; Ohkawara, Masaaki; Linko, Pekka


    Powdery encapsulation of shiitake flavors, extracted from dried shiitake, was investigated by spray drying. Flavor retention increased with an increase in drying air temperature and solid content, and decreased with an increase in dextrose equivalents of maltodextrin. A heat-treatment of the extract liquid made the lenthionine concentration increase, but did not influence the concentrations of the other flavors. The formation of lenthionine with heat-treatment could be described by the consecutive unimolecular-type first order reaction. Lenthionine content in a spray-dried powder prepared with the heated extracted liquid significantly increased. alpha-Cyclodextrin was the most suitable encapsulant of alpha-, beta-, and gamma-cyclodextrins to prepare the spray-dried powder, including lenthionine. The flavor retentions were markedly increased by using of alpha-cyclodextrin and maltodextrin in combination as an encapsulant.

  18. Tight-Binding Description of Impurity States in Semiconductors

    Dominguez-Adame, F.


    Introductory textbooks in solid state physics usually present the hydrogenic impurity model to calculate the energy of carriers bound to donors or acceptors in semiconductors. This model treats the pure semiconductor as a homogeneous medium and the impurity is represented as a fixed point charge. This approach is only valid for shallow impurities…

  19. Fundamentals of semiconductor devices

    Lindmayer, Joseph


    Semiconductor properties ; semiconductor junctions or diodes ; transistor fundamentals ; inhomogeneous impurity distributions, drift or graded-base transistors ; high-frequency properties of transistors ; band structure of semiconductors ; high current densities and mechanisms of carrier transport ; transistor transient response and recombination processes ; surfaces, field-effect transistors, and composite junctions ; additional semiconductor characteristics ; additional semiconductor devices and microcircuits ; more metal, insulator, and semiconductor combinations for devices ; four-pole parameters and configuration rotation ; four-poles of combined networks and devices ; equivalent circuits ; the error function and its properties ; Fermi-Dirac statistics ; useful physical constants.

  20. Sclerosing Encapsulating Peritonitis; Review

    Norman O. Machado


    Full Text Available Sclerosing encapsulating peritonitis (SEP is a rare chronic inflammatory condition of the peritoneum with an unknown aetiology. Also known as abdominal cocoon, the condition occurs when loops of the bowel are encased within the peritoneal cavity by a membrane, leading to intestinal obstruction. Due to its rarity and nonspecific clinical features, it is often misdiagnosed. The condition presents with recurrent episodes of small bowel obstruction and can be idiopathic or secondary; the latter is associated with predisposing factors such as peritoneal dialysis or abdominal tuberculosis. In the early stages, patients can be managed conservatively; however, surgical intervention is necessary for those with advanced stage intestinal obstruction. A literature review revealed 118 cases of SEP; the mean age of these patients was 39 years and 68.0% were male. The predominant presentation was abdominal pain (72.0%, distension (44.9% or a mass (30.5%. Almost all of the patients underwent surgical excision (99.2% without postoperative complications (88.1%.

  1. [Encapsulating peritoneal sclerosis].

    Ryckelynck, Jean-Philippe; Béchade, Clémence; Bouvier, Nicolas; Ficheux, Maxence; Ligny, Bruno Hurault de; Lobbedez, Thierry


    Encapsulating peritoneal sclerosis is a rare but devastating complication of long-term peritoneal dialysis with a high mortality rate. The incidence is between 0.5 and 2.5%, decreasing with time. PSE is defined as a clinical syndrome with signs of gastrointestinal obstruction, inflammation parameters, radiological and macroscopic changes. The duration of treatment and the cessation of peritoneal dialysis are the main risks. About 75% occured in patients on hemodialysis or after kidney transplantation. Morphological alterations are disappearance of mesothelial layer, submesothelial fibrosis, interstitial sclerosis and vasculopathy. Ultrafiltration failure, fast transport status of the peritoneal membrane and loss of sodium sieving, the most powerful predictor, are the functional abnormalities. Biomarkers in peritoneal effluent include cancer antigen 125, interleukin-6. The pathophysiology is probably a consequence of a multiple-hit process in which expression of growth factors and cytokines play a central role. Medical strategies (corticosteroids, tamoxifen) in association with parenteral nutrition and/or surgery (enterolysis) are discussed. Prevention is the use of physiological peritoneal dialysis solutions, icodextrine instead of high glucose concentration solutions and peritoneal lavage after peritoneal dialysis stopping. Copyright © 2017 Société francophone de néphrologie, dialyse et transplantation. Published by Elsevier Masson SAS. All rights reserved.

  2. X-ray absorption spectroscopy of semiconductors

    Ridgway, Mark


    X-ray Absorption Spectroscopy (XAS) is a powerful technique with which to probe the properties of matter, equally applicable to the solid, liquid and gas phases. Semiconductors are arguably our most technologically-relevant group of materials given they form the basis of the electronic and photonic devices that now so widely permeate almost every aspect of our society. The most effective utilisation of these materials today and tomorrow necessitates a detailed knowledge of their structural and vibrational properties. Through a series of comprehensive reviews, this book demonstrates the versatility of XAS for semiconductor materials analysis and presents important research activities in this ever growing field. A short introduction of the technique, aimed primarily at XAS newcomers, is followed by twenty independent chapters dedicated to distinct groups of materials. Topics span dopants in crystalline semiconductors and disorder in amorphous semiconductors to alloys and nanometric material as well as in-sit...

  3. Encapsulated microsensors for reservoir interrogation

    Scott, Eddie Elmer; Aines, Roger D.; Spadaccini, Christopher M.


    In one general embodiment, a system includes at least one microsensor configured to detect one or more conditions of a fluidic medium of a reservoir; and a receptacle, wherein the receptacle encapsulates the at least one microsensor. In another general embodiment, a method include injecting the encapsulated at least one microsensor as recited above into a fluidic medium of a reservoir; and detecting one or more conditions of the fluidic medium of the reservoir.

  4. Encapsulated microsensors for reservoir interrogation

    Scott, Eddie Elmer; Aines, Roger D.; Spadaccini, Christopher M.


    In one general embodiment, a system includes at least one microsensor configured to detect one or more conditions of a fluidic medium of a reservoir; and a receptacle, wherein the receptacle encapsulates the at least one microsensor. In another general embodiment, a method include injecting the encapsulated at least one microsensor as recited above into a fluidic medium of a reservoir; and detecting one or more conditions of the fluidic medium of the reservoir.

  5. The interaction of encapsulated pharmaceutical drugs with a silica matrix.

    Morais, Everton C; Correa, Gabriel G; Brambilla, Rodrigo; Radtke, Claudio; Baibich, Ione Maluf; dos Santos, João Henrique Z


    A series of seven drugs, namely, fluoxetine, gentamicin, lidocaine, morphine, nifedipine, paracetamol and tetracycline, were encapsulated. The encapsulated systems were characterized using a series of complementary techniques: Fourier-transform infrared spectroscopy (FT-IR), diffusive reflectance spectroscopy in the UV-vis region (DRS) and X-ray photoelectron spectroscopy (XPS). According to the DRS spectra, most of the encapsulated systems showed a band shift of the maximum absorption when compared with the corresponding bare pharmaceutical. Additionally, after encapsulation, the drugs exhibited infrared band shifts toward higher wavenumbers, which in turn provided insight into potential sites for interaction with the silica framework. The amine group showed a band shift in the spectra of almost all the drugs (except nifedipine and tetracycline). This finding indicates the possibility of a hydrogen bonding interaction between the drug and the silica via electron donation from the amine group to the silica framework. XPS confirmed this interaction between the pharmaceuticals and the silica through the amine group. A correlation was observed between the textural characteristics of the solids and the spectroscopic data, suggesting that the amine groups from the pharmaceuticals were more perturbed upon encapsulation.

  6. Quantum processes in semiconductors

    Ridley, B K


    Aimed at graduate students, this is a guide to quantum processes of importance in the physics and technology of semiconductors. The fifth edition includes new chapters that expand the coverage of semiconductor physics relevant to its accompanying technology.

  7. Handbook of spintronic semiconductors

    Chen, Weimin


    Offers a review of the field of spintronic semiconductors. This book covers a range of topics, including growth and basic physical properties of diluted magnetic semiconductors based on II-VI, III-V and IV semiconductors, developments in theory and experimental techniques and potential device applications.

  8. Production of 35S for a Liquid Semiconductor Betavoltaic

    Meier, David E.; Garnov, A. Y.; Robertson, J. D.; Kwon, J. W.; Wacharasindhu, T.


    The specific energy density from radioactive decay is five to six orders of magnitude greater than the specific energy density in conventional chemical battery and fuel cell technologies. We are currently investigating the use of liquid semiconductor based betavoltaics as a way to directly convert the energy of radioactive decay into electrical power and potentially avoid the radiation damage that occurs in solid state semiconductor devices due to non-ionizing energy loss. Sulfur-35 was selected as the isotope for the liquid semiconductor demonstrations because it can be produced in high specific activity and it is chemically compatible with known liquid semiconductor media.

  9. Electrical conduction in solid materials physicochemical bases and possible applications

    Suchet, J P


    Electrical Conduction in Solid Materials (Physicochemical Bases and Possible Applications) investigates the physicochemical bases and possible applications of electrical conduction in solid materials, with emphasis on conductors, semiconductors, and insulators. Topics range from the interatomic bonds of conductors to the effective atomic charge in conventional semiconductors and magnetic transitions in switching semiconductors. Comprised of 10 chapters, this volume begins with a description of electrical conduction in conductors and semiconductors, metals and alloys, as well as interatomic bon

  10. Facile encapsulation of oxide based thin film transistors by atomic layer deposition based on ozone.

    Fakhri, Morteza; Babin, Nikolai; Behrendt, Andreas; Jakob, Timo; Görrn, Patrick; Riedl, Thomas


    A simplified encapsulation strategy for metal-oxide based TFTs, using ozone instead of water as an oxygen source in a low-temperature ALD process is demonstrated. Thereby, the threshold voltage remains unaltered and the hysteresis is permanently reduced. Costly energy- and time-consuming post-treatment processes can be avoided. This concept is widely applicable to various encapsulation materials (e.g., Al2 O3 , TiO2 , ZrO2 ) and metal-oxide channel semiconductors (e.g., zinc-tin-oxide (ZTO), indium-gallium-zinc-oxide (IGZO)).

  11. Unitary lens semiconductor device

    Lear, Kevin L.


    A unitary lens semiconductor device and method. The unitary lens semiconductor device is provided with at least one semiconductor layer having a composition varying in the growth direction for unitarily forming one or more lenses in the semiconductor layer. Unitary lens semiconductor devices may be formed as light-processing devices such as microlenses, and as light-active devices such as light-emitting diodes, photodetectors, resonant-cavity light-emitting diodes, vertical-cavity surface-emitting lasers, and resonant cavity photodetectors.

  12. Thin film reactions on alloy semiconductor substrates

    Olson, D.A.


    The interactions between Pt and In{sub .53}Ga{sub .47}As have been studied. In{sub .53}Ga{sub .47}As substrates with 70nm Pt films were encapsulated in SiO{sub 2}, and annealed up to 600{degree}C in flowing forming gas. The composition and morphology of the reaction product phases were studied using x-ray diffraction, Auger depth profiling, and transmission electron microscopy. The reaction kinetics were examined with Rutherford Backscattering. Results show that Pt/In{sub .53}Ga{sub .47}As reacts to form many of the reaction products encountered in the Pt/GaAs and Pt/InP reactions: PtGa, Pt{sub 3}Ga, and PtAs{sub 2}. In addition, a ternary phase, Pt(In:Ga){sub 2}, develops, which is a solid solution between PtIn{sub 2} and PtGa{sub 2}. The amount of Ga in the ternary phase increases with annealing temperature, which causes a decrease in the lattice parameter of the phase. The reaction products show a tendency to form layered structures, especially for higher temperatures and longer annealing times. Unlike the binary case, the PtAs{sub 2}, phase is randomly oriented on the substrate, and is intermingle with a significant amount of Pt(In:Ga){sub 2}. Following Pt/In{sub .53}Ga{sub .47}As reactions, two orientation relationships between the Pt(In:Ga){sub 2} product phase and the substrate were observed, despite the large mismatch with the substrate ({approximately}8%). For many metal/compound semiconductor interactions, the reaction rate is diffusion limited, i.e. exhibits a parabolic dependence on time. An additional result of this study was the development of an In-rich layer beneath the reacted layer. The Auger depth profile showed a substantial increase in the sample at this layer. This is a significant result for the production of ohmic contacts, as the Schottky barrier height in this system lower for higher In concentrations. 216 refs.

  13. Heterogeneous photocatalysis using inorganic semiconductor solids

    Gaya, Umar Ibrahim


    This book introduces the essential principles of photocatalysis and provides an update on its scientific foundations, research advances, current opinions, and interpretations. It explains reaction mechanisms from first principles.

  14. Numerical modelling of melting and settling of an encapsulated PCM using variable viscosity

    Kasibhatla, Raghavendra Rohith; König-Haagen, Andreas; Rösler, Fabian; Brüggemann, Dieter


    Thermal energy storage units using macro-encapsulated PCM in industrial and residential applications are contemporary due to better efficiency during charging and discharging. This article focuses on numerical modelling of the melting process in a macro-encapsulated PCM. Accounting the non-linear enthalpy-temperature relation and ramping down the velocity in solid phase is therefore fundamental. In the present article the variable viscosity method is implemented to ramp down the solid velocity and allow settling of the solid phase. This complete numerical model of melting and settling of PCM in a capsule is implemented in OpenFOAM. The numerical results for different solid viscosities are validated with experiments and show good agreement. The influence of the solid viscosity value and the pressure-velocity convergence is studied. It is observed that the pressure-velocity convergence only plays a greater role in the case where the computation of the exact solid velocity is required.

  15. Carrier scattering in metals and semiconductors

    Gantmakher, VF


    The transport properties of solids, as well as the many optical phenomena in them are determined by the scattering of current carriers. ``Carrier Scattering in Metals and Semiconductors'' elucidates the state of the art in the research on the scattering mechanisms for current carriers in metals and semiconductors and describes experiments in which these mechanisms are most dramatically manifested.The selection and organization of the material is in a form to prepare the reader to reason independently and to deal just as independently with available theoretical results and experimental

  16. Epitaxial GeSn film formed by solid phase epitaxy and its application to Yb{sub 2}O{sub 3}-gated GeSn metal-oxide-semiconductor capacitors with sub-nm equivalent oxide thickness

    Lee, Ching-Wei; Wu, Yung-Hsien; Hsieh, Ching-Heng; Lin, Chia-Chun [Department of Engineering and System Science, National Tsing Hua University, 300 Hsinchu, Taiwan (China)


    Through the technique of solid phase epitaxy (SPE), an epitaxial Ge{sub 0.955}Sn{sub 0.045} film was formed on a Ge substrate by depositing an amorphous GeSn film followed by a rapid thermal annealing at 550 °C. A process that uses a SiO{sub 2} capping layer on the amorphous GeSn film during SPE was proposed and it prevents Sn precipitation from occurring while maintaining a smooth surface due to the reduced surface mobility of Sn atoms. The high-quality epitaxial GeSn film was observed to have single crystal structure, uniform thickness and composition, and tiny surface roughness with root mean square of 0.56 nm. With a SnO{sub x}-free surface, Yb{sub 2}O{sub 3}-gated GeSn metal-oxide-semiconductor (MOS) capacitors with equivalent oxide thickness (EOT) of 0.55 nm were developed. A small amount of traps inside the Yb{sub 2}O{sub 3} was verified by negligible hysteresis in capacitance measurement. Low leakage current of 0.4 A/cm{sup 2} at gate bias of flatband voltage (V{sub FB})-1 V suggests the high quality of the gate dielectric. In addition, the feasibility of using Yb{sub 2}O{sub 3} to well passivate GeSn surface was also evidenced by the small interface trap density (D{sub it}) of 4.02 × 10{sup 11} eV{sup −1} cm{sup −2}, which can be attributed to smooth GeSn surface and Yb{sub 2}O{sub 3} valency passivation. Both leakage current and D{sub it} performance outperform other passivation techniques at sub-nm EOT regime. The proposed epitaxial GeSn film along with Yb{sub 2}O{sub 3} dielectric paves an alternative way to enable high-performance GeSn MOS devices.

  17. Semiconductor Physical Electronics

    Li, Sheng


    Semiconductor Physical Electronics, Second Edition, provides comprehensive coverage of fundamental semiconductor physics that is essential to an understanding of the physical and operational principles of a wide variety of semiconductor electronic and optoelectronic devices. This text presents a unified and balanced treatment of the physics, characterization, and applications of semiconductor materials and devices for physicists and material scientists who need further exposure to semiconductor and photonic devices, and for device engineers who need additional background on the underlying physical principles. This updated and revised second edition reflects advances in semicondutor technologies over the past decade, including many new semiconductor devices that have emerged and entered into the marketplace. It is suitable for graduate students in electrical engineering, materials science, physics, and chemical engineering, and as a general reference for processing and device engineers working in the semicondi...

  18. Microencapsulation of steviol glycosides (Stevia rebaudiana Bertoni by a spray drying method – Evaluation of encapsulated products and prepared syrups

    Charikleia Chranioti


    Full Text Available The aim of this study was to encapsulate the steviol glycosides (SGs, derived from Stevia rebaudiana (Bert Bertoni leaves, by applying a spray-drying method. The purpose was to minimize the bitter aftertaste of the SGs as well as to ameliorate/improve their properties. The encapsulation agents used were maltodextrin (19 DE and inulin in a ratio of 80 : 20, while three levels of SGs in total solids (1.5, 2.5 and 3.5 % were studied. The encapsulated SGs products were evaluated for their hygroscopicity, solubility, moisture content and microencapsulation efficiency (MEE %. Also, syrups prepared with encapsulated SGs, at 1 % w/v, were tested for their viscosity, refractive index, turbidity and sensory properties. Significant differences (P<0.05  in MEE %, moisture content, hygroscopicity and solubility values of the encapsulated SGs products were observed depending on the level of SGs in total solids. In particular, the MEE %, the hygroscopicity and the solubility values ranged from 62.36, 82.46 to 94.67 %, 21.51, 26.67 and 24.25 % and 99.93, 97.50 to 96.03 % for encapsulated SGs products produced with 1.5, 2.5 and 3.5 % SGs in total solids, respectively. The encapsulated product produced with 2.5 % steviol glycosides in total solids presented the most appealing sensory and quality characteristics.

  19. Microencapsulation of steviol glycosides (Stevia rebaudiana Bertoni by a spray drying method – Evaluation of encapsulated products and prepared syrups

    Charikleia Chranioti


    Full Text Available The aim of this study was to encapsulate the steviol glycosides (SGs, derived from Stevia rebaudiana (Bert Bertoni leaves, by applying a spray-drying method. The purpose was to minimize the bitter aftertaste of the SGs as well as to ameliorate/improve their properties. The encapsulation agents used were maltodextrin (19 DE and inulin in a ratio of 80 : 20, while three levels of SGs in total solids (1.5, 2.5 and 3.5 % were studied. The encapsulated SGs products were evaluated for their hygroscopicity, solubility, moisture content and microencapsulation efficiency (MEE %. Also, syrups prepared with encapsulated SGs, at 1 % w/v, were tested for their viscosity, refractive index, turbidity and sensory properties. Significant differences (P<0.05  in MEE %, moisture content, hygroscopicity and solubility values of the encapsulated SGs products were observed depending on the level of SGs in total solids. In particular, the MEE %, the hygroscopicity and the solubility values ranged from 62.36, 82.46 to 94.67 %, 21.51, 26.67 and 24.25 % and 99.93, 97.50 to 96.03 % for encapsulated SGs products produced with 1.5, 2.5 and 3.5 % SGs in total solids, respectively. The encapsulated product produced with 2.5 % steviol glycosides in total solids presented the most appealing sensory and quality characteristics.

  20. Optical properties of zinc oxide clusters encapsulated in a zeolite host

    Türk, T.; Sabin, F.; Vogler, Arnd


    The optical properties of nanometer-sized semiconductor materials are of interest in areas such as photocatalysis and non-linear optics. Ultrasmall zinc oxide particles encapsulated in a porous zeolite (A) host were characterized by powder X-ray diffraction, reflectance, and luminescence spectra. Compared to bulk ZnO the particles show pronounced blue shifts of the reflectance as well as the luminescence bands owing to the quantum size effect.

  1. Asbestos: The Case for Encapsulation.

    Russek, William F.


    Encapsulation has proven to be the safest, surest, and most permanent method of treating sprayed asbestos on ceilings and walls. Federal aid is available to help pay for inspection of school buildings for asbestos and for asbestos removal. (Author/MLF)

  2. Microbes encapsulated within crosslinkable polymers

    Chidambaram, Devicharan; Liu, Ying; Rafailovich, Miriam H


    The invention relates to porous films comprising crosslinked electrospun hydrogel fibers. Viable microbes are encapsulated within the crosslinked electrospun hydrogel fibers. The crosslinked electrospun hydrogel fibers are water insoluble and permeable. The invention also relates to methods of making and using such porous films.

  3. Encapsulation of polymer photovoltaic prototypes

    Krebs, Frederik C


    A simple and efficient method for the encapsulation of polymer and organic photovoltaic prototypes is presented. The method employs device preparation on glass substrates with subsequent sealing using glass fiber reinforced thermosetting epoxy (prepreg) against a back plate. The method allows...

  4. Technology of mammalian cell encapsulation

    Uludag, H; De Vos, P; Tresco, PA


    Entrapment of mammalian cells in physical membranes has been practiced since the early 1950s when it was originally introduced as a basic research tool. The method has since been developed based on the promise of its therapeutic usefulness in tissue transplantation. Encapsulation physically isolates

  5. Dosimetric study of a new polymer encapsulated palladium-103 seed

    Bernard, S; Vynckier, S [Cliniques Universitaires Saint-Luc, Radiotherapy and Oncology Department, Catholic University of Louvain, Brussels (Belgium)


    The use of low-energy photon emitters for brachytherapy applications, as in the treatment of prostate or ocular tumours, has increased significantly over the last few years. Several new seed models utilizing {sup 103}Pd and {sup 125}I have recently been introduced. Following the TG43U1 recommendations of the AAPM (American Association of Physicists in Medicine) (Rivard et al 2004 Med. Phys. 31 633), dose distributions around these low-energy photon emitters are characterized by the dose rate constant, the radial dose function and the anisotropy function in water. These functions and constants can be measured for each new seed in a solid phantom (i.e. solid water such as WT1) using high spatial resolution detectors such as very small thermoluminescent detectors. These experimental results in solid water must then be converted into liquid water by using Monte Carlo simulations. This paper presents the dosimetric parameters of a new palladium seed, OptiSeed{sup TM} (produced by International Brachytherapy (IBt), Seneffe, Belgium), made with a biocompatible polymeric shell and with a design that differs from the hollow titanium encapsulated seed, InterSource{sup 103}, produced by the same company. A polymer encapsulation was chosen by the company IBt in order to reduce the quantity of radioactive material needed for a given dose rate, and to improve the symmetry of the radiation field around the seed. The necessary experimental data were obtained by measurements with LiF thermoluminescent dosimeters (1 mm{sup 3}) in a solid water phantom (WT1) and then converted to values in liquid water using Monte Carlo calculations (MCNP-4C). Comparison of the results with a previous study by Reniers et al (2002 Appl. Radiat. Isot. 57 805) shows very good agreement for the dose rate constant and for the radial dose function. In addition, the results also indicate an improvement in isotropy compared to a conventional titanium encapsulated seed. The relative dose (anisotropy value

  6. Semiconductor Electrical Measurements Laboratory

    Federal Laboratory Consortium — The Semiconductor Electrical Measurements Laboratory is a research laboratory which complements the Optical Measurements Laboratory. The laboratory provides for Hall...

  7. Semiconductor bridge (SCB) detonator

    Bickes, Jr., Robert W.; Grubelich, Mark C.


    The present invention is a low-energy detonator for high-density secondary-explosive materials initiated by a semiconductor bridge igniter that comprises a pair of electrically conductive lands connected by a semiconductor bridge. The semiconductor bridge is in operational or direct contact with the explosive material, whereby current flowing through the semiconductor bridge causes initiation of the explosive material. Header wires connected to the electrically-conductive lands and electrical feed-throughs of the header posts of explosive devices, are substantially coaxial to the direction of current flow through the SCB, i.e., substantially coaxial to the SCB length.

  8. Efficiencies in alginate encapsulation of vegetative explants

    The goal of this study was to improve a non-mechanized bulk encapsulation technique to standardize encapsulation procedures and reduce the labor time compared to encapsulating individual nodes. Four mm-long nodal segments from Stage II cultures of Hibiscus moscheutos L. ‘Lord Baltimore’ were encapsu...

  9. Controlled Chemical Doping of Semiconductor Nanocrystals Using Redox Buffers

    Engel, Jesse H. [Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Surendranath, Yogesh [Univ. of California, Berkeley, CA (United States); Alivisatos, Paul [Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)


    Semiconductor nanocrystal solids are attractive materials for active layers in next-generation optoelectronic devices; however, their efficient implementation has been impeded by the lack of precise control over dopant concentrations. Herein we demonstrate a chemical strategy for the controlled doping of nanocrystal solids under equilibrium conditions. Exposing lead selenide nanocrystal thin films to solutions containing varying proportions of decamethylferrocene and decamethylferrocenium incrementally and reversibly increased the carrier concentration in the solid by 2 orders of magnitude from their native values. This application of redox buffers for controlled doping provides a new method for the precise control of the majority carrier concentration in porous semiconductor thin films.

  10. Fundamentals of semiconductors physics and materials properties

    Yu, Peter Y


    Fundamentals of Semiconductors attempts to fill the gap between a general solid-state physics textbook and research articles by providing detailed explanations of the electronic, vibrational, transport, and optical properties of semiconductors The approach is physical and intuitive rather than formal and pedantic Theories are presented to explain experimental results This textbook has been written with both students and researchers in mind Its emphasis is on understanding the physical properties of Si and similar tetrahedrally coordinated semiconductors The explanations are based on physical insights Each chapter is enriched by an extensive collection of tables of material parameters, figures and problems Many of these problems 'lead the student by the hand' to arrive at the results

  11. Fundamentals of semiconductors physics and materials properties

    Yu, Peter Y


    This fourth edition of the well-established Fundamentals of Semiconductors serves to fill the gap between a general solid-state physics textbook and research articles by providing detailed explanations of the electronic, vibrational, transport, and optical properties of semiconductors. The approach is physical and intuitive rather than formal and pedantic. Theories are presented to explain experimental results. This textbook has been written with both students and researchers in mind. Its emphasis is on understanding the physical properties of Si and similar tetrahedrally coordinated semiconductors. The explanations are based on physical insights. Each chapter is enriched by an extensive collection of tables of material parameters, figures, and problems. Many of these problems "lead the student by the hand" to arrive at the results. The major changes made in the fourth edition include: an extensive appendix about the important and by now well-established deep center known as the DX center, additional problems...

  12. Inherent properties of binary tetrahedral semiconductors

    Verma, A. S.; Sarkar, B. K.; Jindal, V. K.


    A new approach utilising the concept of ionic charge theory has been used to explain the inherent properties such as lattice thermal conductivity and bulk modulus of A IIIB V and A IIB VI semiconductors. The lattice thermal conductivity ( K) of these semiconductors exhibit a linear relationship when plotted on a log-log scale against the nearest neighbour distance d (Å), but fall on two straight lines according to the product of the ionic charge of the compounds. On the basis of this result a simple lattice thermal conductivity-bulk modulus relationship is proposed and used to estimate the bulk modulus of these semiconductors. A fairly good agreement has been found between the experimental and calculated values of these parameters for zinc blende structured solids.

  13. Thin tantalum-silicon-oxygen/tantalum-silicon-nitrogen films as high-efficiency humidity diffusion barriers for solar cell encapsulation

    Heuer, H. [Institut fuer Halbleiter-und Mikrosystemtechnik (IHM) Technische Universitaet Dresden, Helmholtzstrasse 10, 01062 Dresden (Germany)]. E-mail:; Wenzel, C. [Institut fuer Halbleiter-und Mikrosystemtechnik (IHM) Technische Universitaet Dresden, Helmholtzstrasse 10, 01062 Dresden (Germany); Herrmann, D. [Institut fuer Halbleiter-und Mikrosystemtechnik (IHM) Technische Universitaet Dresden, Helmholtzstrasse 10, 01062 Dresden (Germany); Zentrum fuer Sonnenenergie-und Wasserstoff-Forschung (ZSW) Industriestrasse 6, 70565 Stuttgart (Germany); Huebner, R. [Institut fuer Halbleiter-und Mikrosystemtechnik (IHM) Technische Universitaet Dresden, Helmholtzstrasse 10, 01062 Dresden (Germany); Leibniz Institut fuer Festkoerper-und Werkstoffforschung Dresden (IFW) Helmholtzstrasse 20, 01069, Dresden (Germany); Zhang, Z.L. [Institut fuer Halbleiter-und Mikrosystemtechnik (IHM) Technische Universitaet Dresden, Helmholtzstrasse 10, 01062 Dresden (Germany); Max-Planck-Gesellschaft fuer Metallforschung (MPI) Heisenbergstrasse 3, 70569 Stuttgart (Germany); Bartha, J.W. [Institut fuer Halbleiter-und Mikrosystemtechnik (IHM) Technische Universitaet Dresden, Helmholtzstrasse 10, 01062 Dresden (Germany)


    Flexible thin-film solar cells require flexible encapsulation to protect the copper-indium-2 selenide (CIS) absorber layer from humidity and aggressive environmental influences. Tantalum-silicon-based diffusion barriers are currently a favorite material to prevent future semiconductor devices from copper diffusion. In this work tantalum-silicon-nitrogen (Ta-Si-N) and tantalum-silicon-oxygen (Ta-Si-O) films were investigated and optimized for thin-film solar cell encapsulation of next-generation flexible solar modules. CIS solar modules were coated with tantalum-based barrier layers. The performance of the thin-film barrier encapsulation was determined by measuring the remaining module efficiency after a 1000 h accelerated aging test. A significantly enhanced stability against humidity diffusion in comparison to non-encapsulated modules was reached with a reactively sputtered thin-film system consisting of 250 nm Ta-Si-O and 15 nm Ta-Si-N.

  14. Organic Molecular Solids

    Schwoerer, Marcus


    This is the first comprehensive textbook on the physical aspects of organic solids. All phenomena which are necessary in order to understand modern technical applications are being dealt with in a way which makes the concepts of the topics accessible for students. The chapters - from the basics, production and characterization of organic solids and layers to organic semiconductors, superconductors and opto-electronical applications - have been arranged in a logical and well thought-out order.

  15. Semiconductors data handbook

    Madelung, Otfried


    This volume Semiconductors: Data Handbook contains frequently used data from the corresponding larger Landolt-Börnstein handbooks in a low price book for the individual scientist working in the laboratory. The Handbook contain important information about a large number of semiconductors

  16. Applications of Semiconductor Lasers

    LI Te; SUN Yan-fang; NING Yong-qiang; WANG Li-jun


    An overview of the applications of semiconductor lasers is presented. Diode lasers are widely used today,and the most prevalent use of the laser is probably in CD and DVD drives for computers and audio/video media systems. Semiconductor lasers are also used in many other fields ranging from optical fiber communications to display,medicine and pumping sources.

  17. Semiconductor Research Experimental Techniques

    Balkan, Naci


    The book describes the fundamentals, latest developments and use of key experimental techniques for semiconductor research. It explains the application potential of various analytical methods and discusses the opportunities to apply particular analytical techniques to study novel semiconductor compounds, such as dilute nitride alloys. The emphasis is on the technique rather than on the particular system studied.

  18. Semiconductor radiation detection systems


    Covers research in semiconductor detector and integrated circuit design in the context of medical imaging using ionizing radiation. This book explores other applications of semiconductor radiation detection systems in security applications such as luggage scanning, dirty bomb detection and border control.

  19. 柚皮苷固体脂质纳米粒包封率及体外释放度测定%Determination of Encapsulation Efficiency and Release Rate in Vitro of Solid Lipid Nanoparticles Containing Naringin

    张红; 贾小莉; 匡长春; 陈芳芳; 符旭东


    目的:建立柚皮苷固体脂质纳米粒(solid lipid nanoparticles,SLN)的包封率和体外释放度的测定方法.方法:采用超滤法和高效液相色谱法测定柚皮苷SLN包封率.通过透析袋法测定柚皮苷SLN的体外释放度.结果:柚皮苷在2.5~160.0μg·ml-1范围内,线性关系良好(r=0.999 9).平均回收率为99.9%,RSD为1.1%.透析袋对柚皮苷没有吸附作用.柚皮苷SLN包封率为61.3%,体外释药曲线符合一级动力学方程.结论:所建立的方法简单可靠.

  20. Compound Semiconductor Radiation Detectors

    Owens, Alan


    Although elemental semiconductors such as silicon and germanium are standard for energy dispersive spectroscopy in the laboratory, their use for an increasing range of applications is becoming marginalized by their physical limitations, namely the need for ancillary cooling, their modest stopping powers, and radiation intolerance. Compound semiconductors, on the other hand, encompass such a wide range of physical and electronic properties that they have become viable competitors in a number of applications. Compound Semiconductor Radiation Detectors is a consolidated source of information on all aspects of the use of compound semiconductors for radiation detection and measurement. Serious Competitors to Germanium and Silicon Radiation Detectors Wide-gap compound semiconductors offer the ability to operate in a range of hostile thermal and radiation environments while still maintaining sub-keV spectral resolution at X-ray wavelengths. Narrow-gap materials offer the potential of exceeding the spectral resolutio...

  1. The physics of semiconductors an introduction including nanophysics and applications

    Grundmann, Marius


    The 3rd edition of this successful textbook contains ample material for a comprehensive upper-level undergraduate or beginning graduate course, guiding readers to the point where they can choose a special topic and begin supervised research. The textbook provides a balance between essential aspects of solid-state and semiconductor physics, on the one hand, and the principles of various semiconductor devices and their applications in electronic and photonic devices, on the other. It highlights many practical aspects of semiconductors such as alloys, strain, heterostructures, nanostructures, that are necessary in modern semiconductor research but typically omitted in textbooks. Coverage also includes additional advanced topics, such as Bragg mirrors, resonators, polarized and magnetic semiconductors, nanowires, quantum dots, multi-junction solar cells, thin film transistors, carbon-based nanostructures and transparent conductive oxides. The text derives explicit formulas for many results to support better under...

  2. Hydrophobin-Encapsulated Quantum Dots.

    Taniguchi, Shohei; Sandiford, Lydia; Cooper, Maggie; Rosca, Elena V; Ahmad Khanbeigi, Raha; Fairclough, Simon M; Thanou, Maya; Dailey, Lea Ann; Wohlleben, Wendel; von Vacano, Bernhard; de Rosales, Rafael T M; Dobson, Peter J; Owen, Dylan M; Green, Mark


    The phase transfer of quantum dots to water is an important aspect of preparing nanomaterials that are suitable for biological applications, and although numerous reports describe ligand exchange, very few describe efficient ligand encapsulation techniques. In this report, we not only report a new method of phase transferring quantum dots (QDs) using an amphiphilic protein (hydrophobin) but also describe the advantages of using a biological molecule with available functional groups and their use in imaging cancer cells in vivo and other imaging applications.

  3. Enhancing heat capacity of colloidal suspension using nanoscale encapsulated phase-change materials for heat transfer.

    Hong, Yan; Ding, Shujiang; Wu, Wei; Hu, Jianjun; Voevodin, Andrey A; Gschwender, Lois; Snyder, Ed; Chow, Louis; Su, Ming


    This paper describes a new method to enhance the heat-transfer property of a single-phase liquid by adding encapsulated phase-change nanoparticles (nano-PCMs), which absorb thermal energy during solid-liquid phase changes. Silica-encapsulated indium nanoparticles and polymer-encapsulated paraffin (wax) nanoparticles have been made using colloid method, and suspended into poly-alpha-olefin (PAO) and water for potential high- and low-temperature applications, respectively. The shells prevent leakage and agglomeration of molten phase-change materials, and enhance the dielectric properties of indium nanoparticles. The heat-transfer coefficients of PAO containing indium nanoparticles (30% by mass) and water containing paraffin nanoparticles (10% by mass) are 1.6 and 1.75 times higher than those of corresponding single-phase fluids. The structural integrity of encapsulation allows repeated use of such nanoparticles for many cycles in high heat generating devices.

  4. Semiconductor terahertz technology devices and systems at room temperature operation

    Carpintero, G; Hartnagel, H; Preu, S; Raisanen, A


    Key advances in Semiconductor Terahertz (THz) Technology now promises important new applications enabling scientists and engineers to overcome the challenges of accessing the so-called "terahertz gap".  This pioneering reference explains the fundamental methods and surveys innovative techniques in the generation, detection and processing of THz waves with solid-state devices, as well as illustrating their potential applications in security and telecommunications, among other fields. With contributions from leading experts, Semiconductor Terahertz Technology: Devices and Systems at Room Tempe

  5. Picosecond Semiconductor Lasers For Characterizing High-Speed Image Shutters

    Pagano, T. S.; Janson, F. J.; Yates, G. J.; Jaramillo, S. A.


    A portable system that utilizes solid state electronic timing circuits and a pulsed semiconductor laser for characterizing the optical gate sequence of high-speed image shutters, including microchannel-plate intensifier tubes (MCPTs), and silicon-intensified target vidicons (SITVs), is described and compared to earlier methods of characterization. Gate sequences obtained using the system and streak camera data of the semiconductor laser pulse are presented, with a brief discussion of the electronic delay timing and avalanche circuits used in the system.

  6. Process for Encapsulating Protein Crystals

    Morrison, Dennis R.; Mosier, Benjamin


    A process for growing protein crystals encapsulated within membranes has been invented. This process begins with the encapsulation of a nearly saturated aqueous protein solution inside semipermeable membranes to form microcapsules. The encapsulation is effected by use of special formulations of a dissolved protein and a surfactant in an aqueous first liquid phase, which is placed into contact with a second, immiscible liquid phase that contains one or more polymers that are insoluble in the first phase. The second phase becomes formed into the semipermeable membranes that surround microglobules of the first phase, thereby forming the microcapsules. Once formed, the microcapsules are then dehydrated osmotically by exposure to a concentrated salt or polymer solution. The dehydration forms supersaturated solutions inside the microcapsules, thereby enabling nucleation and growth of protein crystals inside the microcapsules. By suitable formulation of the polymer or salt solution and of other physical and chemical parameters, one can control the rate of transport of water out of the microcapsules through the membranes and thereby create physicochemical conditions that favor the growth, within each microcapsule, of one or a few large crystals suitable for analysis by x-ray diffraction. The membrane polymer can be formulated to consist of low-molecular-weight molecules that do not interfere with the x-ray diffraction analysis of the encapsulated crystals. During dehydration, an electrostatic field can be applied to exert additional control over the rate of dehydration. This protein-crystal-encapsulation process is expected to constitute the basis of protein-growth experiments to be performed on the space shuttle and the International Space Station. As envisioned, the experiments would involve the exposure of immiscible liquids to each other in sequences of steps under microgravitational conditions. The experiments are expected to contribute to knowledge of the precise

  7. Coherent dynamics in semiconductors

    Hvam, Jørn Märcher


    Ultrafast nonlinear optical spectroscopy is used to study the coherent dynamics of optically excited electron-hole pairs in semiconductors. Coulomb interaction implies that the optical inter-band transitions are dominated, at least at low temperatures, by excitonic effects. They are further...... and molecular systems are found and studied in the exciton-biexciton system of semiconductors. At densities where strong exciton interactions, or many-body effects, become dominant, the semiconductor Bloch equations present a more rigorous treatment of the phenomena Ultrafast degenerate four-wave mixing is used...

  8. Defects in semiconductors

    Romano, Lucia; Jagadish, Chennupati


    This volume, number 91 in the Semiconductor and Semimetals series, focuses on defects in semiconductors. Defects in semiconductors help to explain several phenomena, from diffusion to getter, and to draw theories on materials' behavior in response to electrical or mechanical fields. The volume includes chapters focusing specifically on electron and proton irradiation of silicon, point defects in zinc oxide and gallium nitride, ion implantation defects and shallow junctions in silicon and germanium, and much more. It will help support students and scientists in their experimental and theoret

  9. Slow Light Semiconductor Laser


    we demonstrate a semiconductor laser with a spectral linewidth of 18 kHz in the telecom band around 1:55um. The views, opinions and/or findings...we demonstrate a semiconductor laser with a spectral linewidth of 18 kHz in the telecom band around 1:55um. Further, the large intracavity field...hybrid Si/III- V platforms Abstract The semiconductor laser is the principal light source powering the world-wide optical fiber network . Ever

  10. Physics of semiconductor devices

    Rudan, Massimo


    This book describes the basic physics of semiconductors, including the hierarchy of transport models, and connects the theory with the functioning of actual semiconductor devices.  Details are worked out carefully and derived from the basic physics, while keeping the internal coherence of the concepts and explaining various levels of approximation. Examples are based on silicon due to its industrial importance. Several chapters are included that provide the reader with the quantum-mechanical concepts necessary for understanding the transport properties of crystals. The behavior of crystals incorporating a position-dependent impurity distribution is described, and the different hierarchical transport models for semiconductor devices are derived (from the Boltzmann transport equation to the hydrodynamic and drift-diffusion models). The transport models are then applied to a detailed description of the main semiconductor-device architectures (bipolar, MOS). The final chapters are devoted to the description of s...

  11. Biggest semiconductor installed


    Scientists and technicians at the European Laboratory for Particle Physics, commonly known by its French acronym CERN (Centre Europen pour la Recherche Nuclaire), have completed the installation of the largest semiconductor silicon detector.

  12. Defects in semiconductor nanostructures

    Vijay A Singh; Manoj K Harbola; Praveen Pathak


    Impurities play a pivotal role in semiconductors. One part in a million of phosphorous in silicon alters the conductivity of the latter by several orders of magnitude. Indeed, the information age is possible only because of the unique role of shallow impurities in semiconductors. Although work in semiconductor nanostructures (SN) has been in progress for the past two decades, the role of impurities in them has been only sketchily studied. We outline theoretical approaches to the electronic structure of shallow impurities in SN and discuss their limitations. We find that shallow levels undergo a SHADES (SHAllow-DEep-Shallow) transition as the SN size is decreased. This occurs because of the combined effect of quantum confinement and reduced dielectric constant in SN. Level splitting is pronounced and this can perhaps be probed by ESR and ENDOR techniques. Finally, we suggest that a perusal of literature on (semiconductor) cluster calculations carried out 30 years ago would be useful.

  13. A semiconductor laser

    Naoko, O.; Masaru, K.


    A semiconductor laser with enhanced characteristics is patented in which bleaching coatings are generated on the outcoupling mirrors by sputtering alternating coating layers made from A1203 and A10, with high and low indices of refraction.

  14. Harvesting Solar Energy by Means of Charge-Separating Nanocrystals and Their Solids

    Diederich, Geoffrey; O'Connor, Timothy; Moroz, Pavel; Kinder, Erich; Kohn, Elena; Perera, Dimuthu; Lorek, Ryan; Lambright, Scott; Imboden, Martene; Zamkov, Mikhail


    composite two-layer solid of PbS and TiO2 films. In this configuration, photoinduced electrons are injected into TiO2 and are subsequently picked up by an FTO electrode, while holes are channeled to a Au electrode via PbS layer6. To develop the latter we introduce a Semiconductor Matrix Encapsulated Nanocrystal Arrays (SMENA) strategy, which allows bonding PbS NCs into the surrounding matrix of CdS semiconductor. As a result, fabricated solids exhibit excellent thermal stability, attributed to the heteroepitaxial structure of nanocrystal-matrix interfaces, and show compelling light-harvesting performance in prototype solar cells7. PMID:22951526

  15. Harvesting solar energy by means of charge-separating nanocrystals and their solids.

    Diederich, Geoffrey; O'Connor, Timothy; Moroz, Pavel; Kinder, Erich; Kohn, Elena; Perera, Dimuthu; Lorek, Ryan; Lambright, Scott; Imboden, Martene; Zamkov, Mikhail


    composite two-layer solid of PbS and TiO2 films. In this configuration, photoinduced electrons are injected into TiO2 and are subsequently picked up by an FTO electrode, while holes are channeled to a Au electrode via PbS layer. To develop the latter we introduce a Semiconductor Matrix Encapsulated Nanocrystal Arrays (SMENA) strategy, which allows bonding PbS NCs into the surrounding matrix of CdS semiconductor. As a result, fabricated solids exhibit excellent thermal stability, attributed to the heteroepitaxial structure of nanocrystal-matrix interfaces, and show compelling light-harvesting performance in prototype solar cells.

  16. Modeling of semiconductor nanostructures and semiconductor-electrolyte interfaces

    Birner, Stefan


    The main objective of Part I is to give an overview of some of the methods that have been implemented into the nextnano{sup 3} software. Examples are discussed that give insight into doping, strain and mobility. Applications of the single-band Schroedinger equation include three-dimensional superlattices, and a qubit that is manipulated by a magnetic field. Results of the multi-band k.p method are presented for HgTe-CdTe and InAs-GaSb superlattices, and for a SiGe-Si quantum cascade structure. Particular focus is put on a detailed description of the contact block reduction (CBR) method that has been developed within our research group. By means of this approach, quantum transport in the ballistic limit in one, two and three dimensions can be calculated. I provide a very detailed description of the algorithm and present several well documented examples that highlight the key points of this method. Calculating quantum transport in three dimensions is a very challenging task where computationally efficient algorithms - apart from the CBR method - are not available yet. Part II describes the methods that I have implemented into the nextnano{sup 3} software for calculating systems that consist of a combination of semiconductor materials and liquids. These biosensors have a solid-electrolyte interface, and the charges in the solid and in the electrolyte are coupled to each other through the Poisson-Boltzmann equation. I apply this model to a silicon based protein sensor, where I solve the Schroedinger equation together with the Poisson-Boltzmann equation self-consistently, and compare theoretical results with experiment. Furthermore, I have developed a novel approach to model the charge density profiles at semiconductor-electrolyte interfaces that allows us to distinguish hydrophobic and hydrophilic interfaces. Our approach extends previous work where ion specific potentials of mean force describe the distribution of ion species at the interface. I apply this new model

  17. Bacteria-mediated in vivo delivery of quantum dots into solid tumor

    Liu, Ying [Single-molecule and Nanobiology Lab., Dept. of Biophysics, School of Basic Medical Sciences, Peking University, No. 38 Xue Yuan Road, Beijing 100091 (China); Zhou, Mei [Dept. of Radiation Medicine, School of Basic Medical Sciences, Peking University, No. 38 Xue Yuan Road, Beijing 100091 (China); Luo, Dan; Wang, Lijun; Hong, Yuankai [Single-molecule and Nanobiology Lab., Dept. of Biophysics, School of Basic Medical Sciences, Peking University, No. 38 Xue Yuan Road, Beijing 100091 (China); Yang, Yepeng, E-mail: [Dept. of Radiation Medicine, School of Basic Medical Sciences, Peking University, No. 38 Xue Yuan Road, Beijing 100091 (China); Sha, Yinlin, E-mail: [Single-molecule and Nanobiology Lab., Dept. of Biophysics, School of Basic Medical Sciences, Peking University, No. 38 Xue Yuan Road, Beijing 100091 (China); Biomed-X Center, Peking University, Peking University, No. 38 Xue Yuan Road, Beijing 100091 (China)


    Highlights: Black-Right-Pointing-Pointer New approach using the probiotic Bifidobacterium bifidum as a vehicle to deliver QDs into the deep tissue of solid tumors in vivo was achieved. Black-Right-Pointing-Pointer Bifidobacterium bifidum delivery system has intrinsic biocompatibility. Black-Right-Pointing-Pointer The targeting efficacy was improved by folic acids. -- Abstract: Semiconductor nanocrystals, so-called quantum dots (QDs), promise potential application in bioimaging and diagnosis in vitro and in vivo owing to their high-quality photoluminescence and excellent photostability as well as size-tunable spectra. Here, we describe a biocompatible, comparatively safe bacteria-based system that can deliver QDs specifically into solid tumor of living animals. In our strategy, anaerobic bacterium Bifidobacterium bifidum (B. bifidum) that colonizes selectively in hypoxic regions of animal body was successfully used as a vehicle to load with QDs and transported into the deep tissue of solid tumors. The internalization of lipid-encapsuled QDs into B. bifidum was conveniently carried by electroporation. To improve the efficacy and specificity of tumor targeting, the QDs-carrying bacterium surface was further conjugated with folic acids (FAs) that can bind to the folic acid receptor overexpressed tumor cells. This new approach opens a pathway for delivering different types of functional cargos such as nanoparticles and drugs into solid tumor of live animals for imaging, diagnosis and therapy.

  18. Encapsulation methods for organic electrical devices

    Blum, Yigal D.; Chu, William Siu-Keung; MacQueen, David Brent; Shi, Yijian


    The disclosure provides methods and materials suitable for use as encapsulation barriers in electronic devices. In one embodiment, for example, there is provided an electroluminescent device or other electronic device encapsulated by alternating layers of a silicon-containing bonding material and a ceramic material. The encapsulation methods provide, for example, electronic devices with increased stability and shelf-life. The invention is useful, for example, in the field of microelectronic devices.

  19. Radiation effects in semiconductors


    There is a need to understand and combat potential radiation damage problems in semiconductor devices and circuits. Written by international experts, this book explains the effects of radiation on semiconductor devices, radiation detectors, and electronic devices and components. These contributors explore emerging applications, detector technologies, circuit design techniques, new materials, and innovative system approaches. The text focuses on how the technology is being used rather than the mathematical foundations behind it. It covers CMOS radiation-tolerant circuit implementations, CMOS pr


    This state-of-the-art survey on silicon carbide for semiconductors includes a bibliography of the most important references published as of the end...of 1964. The various methods used for growing silicon carbide single crystals are reviewed, as well as their properties and devices fabricated from...them. The fact that the state of-the-art of silicon carbide semiconductors is not further advanced may be attributed to the difficulties of growing

  1. Plastic encapsulated, dye sensitised photovoltaic cells

    Potter, R.J.; Otley, L.C.; Durrant, J.R.; Haque, S.; Xu, C. [Imperial College of Science, Technology and Medicine, London (United Kingdom); Holmes, A.B.; Park, T.; Schulte, N. [Cambridge Univ. (United Kingdom)


    The report presents the results of a collaborative project that aimed to demonstrate the technical feasibility of a plastic-encapsulated, solid state, dye-sensitised solar cell (DSSC) with an energy conversion efficiency (ECE) of at least 3%. DSSCs offer a possible 'step change' in photovoltaic technology resulting in lower costs compared with existing technologies. The project involved a series of eight main tasks: the development of first and second generation HTM electrolytes; the development of polymer-supported electrolytes; the development of low temperature electrode coating procedures; dye development; cell assembly and testing; component integration; and overall process development. A wide range of innovative HTMs have been synthesised, including materials incorporating both hole-transporting and ion-chelating functional groups. The ruthenium-based dye, N3, remained the preferred sensitising component. The project has produced a system that can routinely achieve over 5% ECE at 0.1 Sun illumination on 1 cm{sup 2} cells using polymer-supported electrolytes.

  2. Biological applications of zinc imidazole framework through protein encapsulation

    Kumar, Pawan; Bansal, Vasudha; Paul, A. K.; Bharadwaj, Lalit M.; Deep, Akash; Kim, Ki-Hyun


    The robustness of biomolecules is always a significant challenge in the application of biostorage in biotechnology or pharmaceutical research. To learn more about biostorage in porous materials, we investigated the feasibility of using zeolite imidazolate framework (ZIF-8) with respect to protein encapsulation. Here, bovine serum albumin (BSA) was selected as a model protein for encapsulation with the synthesis of ZIF-8 using water as a media. ZIF-8 exhibited excellent protein adsorption capacity through successive adsorption of free BSA with the formation of hollow crystals. The loading of protein in ZIF-8 crystals is affected by the molecular weight due to diffusion-limited permeation inside the crystals and also by the affinity of the protein to the pendent group on the ZIF-8 surface. The polar nature of BSA not only supported adsorption on the solid surface, but also enhanced the affinity of crystal spheres through weak coordination interactions with the ZIF-8 framework. The novel approach tested in this study was therefore successful in achieving protein encapsulation with porous, biocompatible, and decomposable microcrystalline ZIF-8. The presence of both BSA and FITC-BSA in ZIF-8 was confirmed consistently by spectroscopy as well as optical and electron microscopy.

  3. Pigment encapsulation by emulsion polymerization using macro-RAFT copolymers.

    Nguyen, Duc; Zondanos, Hollie S; Farrugia, Jason M; Serelis, Algirdas K; Such, Chris H; Hawkett, Brian S


    A new method is described, based on living amphipathic random macro-RAFT copolymers, which enables the efficient polymeric encapsulation of both inorganic and organic particulate materials via free-radical polymerization. The mechanism for this new approach is examined in the context of the polymer coating of zirconia- and alumina-coated titanium dioxide particles and its breadth of application demonstrated by the coating of organic phthalocyanine blue pigment particles. The particulate materials were first dispersed in water using a macro-RAFT copolymer as a stabilizer. Monomer and water-soluble initiator were then added to the system, and the monomer polymerized to form the coating. If nucleation of new polymer particles in the aqueous phase was to be avoided, it was found necessary to use a macro-RAFT copolymer that did not form micelles; within this constraint, a broad range of RAFT agents could be used. The macro-RAFT agents used in this work were found not to transfer competitively in the aqueous phase and therefore did not support growth of aqueous-phase polymer. Successful encapsulation of particles was demonstrated by TEM. The process described enables 100% of the particles to be encapsulated with greater than 95% of the polymer finishing up in the polymeric shells around the particles. Moreover, the coating reaction can be carried out at greater than 50% solids in many cases and avoids the agglomeration of particles during the coating step.

  4. Biological applications of zinc imidazole framework through protein encapsulation

    Pawan Kumar


    Full Text Available Abstract The robustness of biomolecules is always a significant challenge in the application of biostorage in biotechnology or pharmaceutical research. To learn more about biostorage in porous materials, we investigated the feasibility of using zeolite imidazolate framework (ZIF-8 with respect to protein encapsulation. Here, bovine serum albumin (BSA was selected as a model protein for encapsulation with the synthesis of ZIF-8 using water as a media. ZIF-8 exhibited excellent protein adsorption capacity through successive adsorption of free BSA with the formation of hollow crystals. The loading of protein in ZIF-8 crystals is affected by the molecular weight due to diffusion-limited permeation inside the crystals and also by the affinity of the protein to the pendent group on the ZIF-8 surface. The polar nature of BSA not only supported adsorption on the solid surface, but also enhanced the affinity of crystal spheres through weak coordination interactions with the ZIF-8 framework. The novel approach tested in this study was therefore successful in achieving protein encapsulation with porous, biocompatible, and decomposable microcrystalline ZIF-8. The presence of both BSA and FITC–BSA in ZIF-8 was confirmed consistently by spectroscopy as well as optical and electron microscopy.

  5. Biodegradable core-shell carriers for simultaneous encapsulation of synergistic actives.

    Windbergs, Maike; Zhao, Yuanjin; Heyman, John; Weitz, David A


    Simultaneous encapsulation of multiple active substances in a single carrier is essential for therapeutic applications of synergistic combinations of drugs. However, traditional carrier systems often lack efficient encapsulation and release of incorporated substances, particularly when combinations of drugs must be released in concentrations of a prescribed ratio. We present a novel biodegradable core-shell carrier system fabricated in a one-step, solvent-free process on a microfluidic chip; a hydrophilic active (doxorubicin hydrochloride) is encapsulated in the aqueous core, while a hydrophobic active (paclitaxel) is encapsulated in the solid shell. Particle size and composition can be precisely controlled, and core and shell can be individually loaded with very high efficiency. Drug-loaded particles can be dried and stored as a powder. We demonstrate the efficacy of this system through the simultaneous encapsulation and controlled release of two synergistic anticancer drugs using two cancer-derived cell lines. This solvent-free platform technology is also of high potential value for encapsulation of other active ingredients and chemical reagents.

  6. Thermal-capillary analysis of Czochralski and liquid encapsulated Czochralski crystal growth

    Derby, J. J.; Brown, R. A.


    Results are presented from finite element analysis of the Czochralski (CZ) and Liquid Encapsulated Czochralski (LEC) crystal growth processes based on a thermal-capillary model which governs the heat transfer in the system simultaneously with setting the shapes of the melt/solid interface, the melt and encapsulant menisci, and the radius of a steadily growing crystal. Calculations are performed for the small-scale growth of silicon (CZ) and gallium arsenide (LEC). The effects of melt volume and crucible position relative to the heater on the radius of the crystal and the shape of the melt/solid interface are predicted for the CZ system, and the importance of including an accurate representation of the melt meniscus for modeling the process is demonstrated. The additional effect of an encapsulant layer on heat transfer is treated for the LEC method for the cases of totally transparent and opaque encapsulant. The responses of these LEC prototype systems are examined for changes in pull rate and encapsulant volume.

  7. Semiconductor photocatalysis--mechanistic and synthetic aspects.

    Kisch, Horst


    Preceding work on photoelectrochemistry at semiconductor single-crystal electrodes has formed the basis for the tremendous growth in the three last decades in the field of photocatalysis at semiconductor powders. The reason for this is the unique ability of inorganic semiconductor surfaces to photocatalyze concerted reduction and oxidation reactions of a large variety of electron-donor and -acceptor substrates. Whereas great attention was paid to water splitting and the exhaustive aerobic degradation of pollutants, only a small amount of research also explored synthetic aspects. After introducing the basic mechanistic principles, standard experiments for the preparation and characterization of visible light active photocatalysts as well as the investigation of reaction mechanisms are discussed. Novel atom-economic C-C and C-N coupling reactions illustrate the relevance of semiconductor photocatalysis for organic synthesis, and demonstrate that the multidisciplinary field combines classical photochemistry with electrochemistry, solid-state chemistry, and heterogeneous catalysis. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Diamagnetic excitons and exciton magnetopolaritons in semiconductors

    Seisyan, R. P.


    Interband magneto-absorption in semiconductors is reviewed in the light of the diamagnetic exciton (DE) concept. Beginning with a proof of the exciton nature of oscillating-magnetoabsorption (the DE discovery), development of the DE concept is discussed, including definition of observation conditions, quasi-cubic approximation for hexagonal crystals, quantum-well effects in artificial structures, and comprehension of an important role of the DE polariton. The successful use of the concept application to a broad range of substances is reviewed, namely quasi-Landau magnetic spectroscopy of the ‘Rydberg’ exciton states in cubic semiconductors such as InP and GaAs and in hexagonal ones such as CdSe, the proof of exciton participation in the formation of optical spectra in narrow-gap semiconductors such as InSb, InAs, and, especially, PbTe, observation of DE spectra in semiconductor solid solutions like InGaAs. The most fundamental findings of the DE spectroscopy for various quantum systems are brought together, including the ‘Coulomb-well’ effect, fine structure of discrete oscillatory states in the InGaAs/GaAs multiple quantum wells, the magneto-optical observation of above-barrier exciton. Prospects of the DE physics in ultrahigh magnetic field are discussed, including technological creation of controllable low-dimensional objects with extreme oscillator strengths, formation of magneto-quantum exciton polymer, and even modelling of the hydrogen behaviour in the atmosphere of a neutron star.

  9. Thin-film encapsulation of organic electronic devices based on vacuum evaporated lithium fluoride as protective buffer layer

    Peng, Yingquan; Ding, Sihan; Wen, Zhanwei; Xu, Sunan; Lv, Wenli; Xu, Ziqiang; Yang, Yuhuan; Wang, Ying; Wei, Yi; Tang, Ying


    Encapsulation is indispensable for organic thin-film electronic devices to ensure reliable operation and long-term stability. For thin-film encapsulating organic electronic devices, insulating polymers and inorganic metal oxides thin films are widely used. However, spin-coating of insulating polymers directly on organic electronic devices may destroy or introduce unwanted impurities in the underlying organic active layers. And also, sputtering of inorganic metal oxides may damage the underlying organic semiconductors. Here, we demonstrated that by utilizing vacuum evaporated lithium fluoride (LiF) as protective buffer layer, spin-coated insulating polymer polyvinyl alcohol (PVA), and sputtered inorganic material Er2O3, can be successfully applied for thin film encapsulation of copper phthalocyanine (CuPc)-based organic diodes. By encapsulating with LiF/PVA/LiF trilayer and LiF/Er2O3 bilayer films, the device lifetime improvements of 10 and 15 times can be achieved. These methods should be applicable for thin-film encapsulation of all kinds of organic electronic devices. Moisture-induced hole trapping, and Al top electrode oxidation are suggest to be the origins of current decay for the LiF/PVA/LiF trilayer and LiF/Er2O3 bilayer films encapsulated devices, respectively.

  10. Mechanical and thermoelectric properties of Bi2-xSbxTe3 prepared by using encapsulated melting and hot pressing

    Jung, Woo-Jin; Kim, Il-Ho


    Bi2-xSbxTe3 ( x = 1.4 - 1.7) solid solutions were synthesized by using encapsulated melting (EM) and were consolidated by using hot pressing (HP). The lattice constants decreased with increasing Sb content, which indicated that solid solutions were successfully synthesized. The relative densities of all the hot-pressed specimens were higher than 97.9 %. X-ray diffraction patterns, pole figures and electron backscattered diffraction spectra of all the hot-pressed specimens indicated randomly oriented textures. Very low values of the orientation factor (F) were obtained, Fmin = 0.008 for Bi0.4Sb1.6Te3 hot-pressed at 673 K and Fmax = 0.115 for Bi0.4Sb1.6Te3 hot-pressed at 723 K, which implied that the microstructures were highly isotropic. A bending strength of 46 MPa and a Vickers hardness of 94 Hv were attained for Bi0.4Sb1.6Te3 hot-pressed at 648 K. However, the mechanical properties were degraded with increasing HP temperature owing to grain growth. An increased HP temperature did not affect the electrical properties significanctly. The carrier concentration increased with increasing Sb content, and the specimen with x = 1.4 showed nondegenerate semiconductor behavior whereas those with x ≥ 1.5 behaved as degenerate semiconductors. All specimens showed p-type conduction, which was confirmed from the positive signs of the Seebeck coefficient and the Hall coefficient. The increased Sb content caused a shift in the peak values of the Seebeck coefficient to higher temperatures and an enhancement of the power factor. The electronic thermal conductivity decreased, but the lattice thermal conductivity increased, with increasing Sb content. The lowest theraml conductivity of 0.83 Wm -1K -1 was obtained at 373 K for Bi0.4Sb1.6Te3. The maximum dimensionless figure of merit, ZT max = 1.1, was achieved at 323 K for Bi0.4Sb1.6Te3.

  11. Encapsulation and characterization of controlled release flurbiprofen loaded microspheres using beeswax as an encapsulating agent.

    Ranjha, Nazar M; Khan, Hafeezullah; Naseem, Shahzad


    The aim of the present study was to extend the use of flurbiprofen in clinical settings by avoiding its harmful gastric effects. For this purpose, we designed the controlled release solid lipid flurbiprofen microspheres (SLFM) by emulsion congealing technique. Drug was entrapped into gastro resistant biodegradable beeswax microspheres which were prepared at different drug/beeswax ratios 1:1, 1:2 and 1:3 using gelatin and tween 20 as emulsifying agents. The effect of emulsifiers and the effect drug/beeswax ratios were studied on hydration rate, encapsulating efficiency, micromeritic properties, scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), X-ray diffraction (X-RD) analysis and in vitro drug release at pH 1.2 for 2 h and at pH 6.8 for 10 h. SEM revealed that microspheres made with tween 20 were smooth while microspheres made with gelatin showed porous morphology, however, they were all spherical in nature. The practical yield (recovery) showed a dependence on drug-beeswax ratio and it was variable from 53 to 84%. High loading encapsulating efficiency of flurbiprofen from 8 to 94% was achieved. FTIR and DSC analysis confirmed the absence of any drug polymer interaction indicating drug stability during microencapsulation. X-RD of pure flurbiprofen shows sharp peaks, which decreases on encapsulation, indicating decrease in the crystallinity of drug in microspheres. The micromeritic studies confirmed the presence of excellent and good flow properties of microspheres. Entrapment efficiency, morphology, practical yield, hydration rate, flow properties demonstrated their dependence on the HLB value of emulsifiers and emulsifiers with higher HLB were found more appropriate for effective microencapsulation of flurbiprofen. The release kinetics followed zero order mechanism of drug release at pH 6.8. Release pattern depends on the morphology of flurbiprofen microspheres and amount of beeswax used in

  12. Different encapsulation strategies for implanted electronics

    Winkler Sebastian


    Full Text Available Recent advancements in implant technology include increasing application of electronic systems in the human body. Hermetic encapsulation of electronic components is necessary, specific implant functions and body environments must be considered. Additional functions such as wireless communication systems require specialized technical solutions for the encapsulation.

  13. Solid0Core Heat-Pipe Nuclear Batterly Type Reactor

    Ehud Greenspan


    This project was devoted to a preliminary assessment of the feasibility of designing an Encapsulated Nuclear Heat Source (ENHS) reactor to have a solid core from which heat is removed by liquid-metal heat pipes (HP).

  14. Encapsulation of probiotic bacteria in biopolymeric system.

    Huq, Tanzina; Khan, Avik; Khan, Ruhul A; Riedl, Bernard; Lacroix, Monique


    Encapsulation of probiotic bacteria is generally used to enhance the viability during processing, and also for the target delivery in gastrointestinal tract. Probiotics are used with the fermented dairy products, pharmaceutical products, and health supplements. They play a great role in maintaining human health. The survival of these bacteria in the human gastrointestinal system is questionable. In order to protect the viability of the probiotic bacteria, several types of biopolymers such as alginate, chitosan, gelatin, whey protein isolate, cellulose derivatives are used for encapsulation and several methods of encapsulation such as spray drying, extrusion, emulsion have been reported. This review focuses on the method of encapsulation and the use of different biopolymeric system for encapsulation of probiotics.

  15. Beyond amorphous organic semiconductors

    Hanna, Jun-ichi


    Recently it has been discovered that some types of liquid crystals, which believed to be governed by ionic conduction, exhibit a very fast electronic conduction. Their charge carrier transport is characterized by high mobility over 10-2 cm2/Vs independent of electric field and temperature. Now, the liquid crystals are being recognized as a new class of organic semiconductors. In this article, a new aspect of liquid crystals as a self-organizing molecular semiconductor are reviewed, focused on their basic charge carrier transport properties and discussed in comparison with those of molecular crystals and amorphous materials. And it is concluded that the liquid crystal is promising as a quality organic semiconductor for the devices that require a high mobility.

  16. Photoelectronic properties of semiconductors

    Bube, Richard H


    The interaction between light and electrons in semiconductors forms the basis for many interesting and practically significant properties. This book examines the fundamental physics underlying this rich complexity of photoelectronic properties of semiconductors, and will familiarise the reader with the relatively simple models that are useful in describing these fundamentals. The basic physics is also illustrated with typical recent examples of experimental data and observations. Following introductory material on the basic concepts, the book moves on to consider a wide range of phenomena, including photoconductivity, recombination effects, photoelectronic methods of defect analysis, photoeffects at grain boundaries, amorphous semiconductors, photovoltaic effects and photoeffects in quantum wells and superlattices. The author is Professor of Materials Science and Electrical Engineering at Stanford University, and has taught this material for many years. He is an experienced author, his earlier books having fo...

  17. Semiconductors for organic transistors

    Antonio Facchetti


    Full Text Available Organic molecules/polymers with a π-conjugated (heteroaromatic backbone are capable of transporting charge and interact efficiently with light. Therefore, these systems can act as semiconductors in opto-electronic devices similar to inorganic materials. However, organic chemistry offers tools for tailoring materials' functional properties via modifications of the molecular/monomeric units, opening new possibilities for inexpensive device manufacturing. This article reviews the fundamental aspects behind the structural design/realization of p- (hole transporting and n-channel (electron-transporting semiconductors for organic field-effect transistors (OFETs. An introduction to OFET principles and history, as well as of the state-of-the-art organic semiconductor structure and performance of OFETs is provided.

  18. Fundamentals of semiconductor lasers

    Numai, Takahiro


    This book explains physics under the operating principles of semiconductor lasers in detail based on the experience of the author, dealing with the first manufacturing of phase-shifted DFB-LDs and recent research on transverse modes.   The book also bridges a wide gap between journal papers and textbooks, requiring only an undergraduate-level knowledge of electromagnetism and quantum mechanics, and helps readers to understand journal papers where definitions of some technical terms vary, depending on the paper. Two definitions of the photon density in the rate equations and two definitions of the phase-shift in the phase-shifted DFB-LD are explained, and differences in the calculated results are indicated, depending on the definitions.    Readers can understand the physics of semiconductor lasers and analytical tools for Fabry-Perot LDs, DFB-LDs, and VCSELs and will be stimulated to develop semiconductor lasers themselves.

  19. Hydrogen in semiconductors II

    Nickel, Norbert H; Weber, Eicke R; Nickel, Norbert H


    Since its inception in 1966, the series of numbered volumes known as Semiconductors and Semimetals has distinguished itself through the careful selection of well-known authors, editors, and contributors. The "Willardson and Beer" Series, as it is widely known, has succeeded in publishing numerous landmark volumes and chapters. Not only did many of these volumes make an impact at the time of their publication, but they continue to be well-cited years after their original release. Recently, Professor Eicke R. Weber of the University of California at Berkeley joined as a co-editor of the series. Professor Weber, a well-known expert in the field of semiconductor materials, will further contribute to continuing the series' tradition of publishing timely, highly relevant, and long-impacting volumes. Some of the recent volumes, such as Hydrogen in Semiconductors, Imperfections in III/V Materials, Epitaxial Microstructures, High-Speed Heterostructure Devices, Oxygen in Silicon, and others promise that this tradition ...

  20. Point contacts in encapsulated graphene

    Handschin, Clevin [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Swiss Nanoscience Institute, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Fülöp, Bálint; Csonka, Szabolcs [Department of Physics, Budapest University of Technology and Economics and Condensed Matter Research Group of the Hungarian Academy of Sciences, Budafoki ut 8, 1111 Budapest (Hungary); Makk, Péter; Blanter, Sofya; Weiss, Markus; Schönenberger, Christian, E-mail: [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Watanabe, Kenji; Taniguchi, Takashi [National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044 (Japan)


    We present a method to establish inner point contacts with dimensions as small as 100 nm on hexagonal boron nitride (hBN) encapsulated graphene heterostructures by pre-patterning the top-hBN in a separate step prior to dry-stacking. 2- and 4-terminal field effect measurements between different lead combinations are in qualitative agreement with an electrostatic model assuming point-like contacts. The measured contact resistances are 0.5–1.5 kΩ per contact, which is quite low for such small contacts. By applying a perpendicular magnetic field, an insulating behaviour in the quantum Hall regime was observed, as expected for inner contacts. The fabricated contacts are compatible with high mobility graphene structures and open up the field for the realization of several electron optical proposals.

  1. Luminescent Colloidal Semiconductor Nanocrystals Containing Copper: Synthesis, Photophysics, and Applications.

    Knowles, Kathryn E; Hartstein, Kimberly H; Kilburn, Troy B; Marchioro, Arianna; Nelson, Heidi D; Whitham, Patrick J; Gamelin, Daniel R


    Copper-doped semiconductors are classic phosphor materials that have been used in a variety of applications for many decades. Colloidal copper-doped semiconductor nanocrystals have recently attracted a great deal of interest because they combine the solution processability and spectral tunability of colloidal nanocrystals with the unique photoluminescence properties of copper-doped semiconductor phosphors. Although ternary and quaternary semiconductors containing copper, such as CuInS2 and Cu2ZnSnS4, have been studied primarily in the context of their photovoltaic applications, when synthesized as colloidal nanocrystals, these materials have photoluminescence properties that are remarkably similar to those of copper-doped semiconductor nanocrystals. This review focuses on the luminescent properties of colloidal copper-doped, copper-based, and related copper-containing semiconductor nanocrystals. Fundamental investigations into the luminescence of copper-containing colloidal nanocrystals are reviewed in the context of the well-established luminescence mechanisms of bulk copper-doped semiconductors and copper(I) molecular coordination complexes. The use of colloidal copper-containing nanocrystals in applications that take advantage of their luminescent properties, such as bioimaging, solid-state lighting, and luminescent solar concentrators, is also discussed.

  2. Conductors, semiconductors, superconductors. An introduction to solid-state physics. For physicists, engineers, and natural scientists; Leiter, Halbleiter, Supraleiter. Eine Einfuehrung in die Festkoerperphysik. Fuer Physiker, Ingenieure und Naturwissenschaftler

    Huebener, Rudolf


    The present book gives an introduction to the foundations of solid-state physics, whereby also the contributing persons and their environment are illuminated. The main topic lies in the electrical and magnetical material properties.

  3. Optical processes in semiconductors

    Pankove, Jacques I


    Based on a series of lectures at Berkeley, 1968-1969, this is the first book to deal comprehensively with all of the phenomena involving light in semiconductors. The author has combined, for the graduate student and researcher, a great variety of source material, journal research, and many years of experimental research, adding new insights published for the first time in this book.Coverage includes energy states in semiconductors and their perturbation by external parameters, absorption, relationships between optical constants, spectroscopy, radiative transitions, nonradiative recombination

  4. Compound semiconductor device physics

    Tiwari, Sandip


    This book provides one of the most rigorous treatments of compound semiconductor device physics yet published. A complete understanding of modern devices requires a working knowledge of low-dimensional physics, the use of statistical methods, and the use of one-, two-, and three-dimensional analytical and numerical analysis techniques. With its systematic and detailed**discussion of these topics, this book is ideal for both the researcher and the student. Although the emphasis of this text is on compound semiconductor devices, many of the principles discussed will also be useful to those inter

  5. Ternary chalcopyrite semiconductors

    Shay, J L; Pamplin, B R


    Ternary Chalcopyrite Semiconductors: Growth, Electronic Properties, and Applications covers the developments of work in the I-III-VI2 and II-IV-V2 ternary chalcopyrite compounds. This book is composed of eight chapters that focus on the crystal growth, characterization, and applications of these compounds to optical communications systems. After briefly dealing with the status of ternary chalcopyrite compounds, this book goes on describing the crystal growth of II-IV-V2 and I-III-VI2 single crystals. Chapters 3 and 4 examine the energy band structure of these semiconductor compounds, illustrat

  6. Advances in semiconductor lasers

    Coleman, James J; Jagadish, Chennupati


    Semiconductors and Semimetals has distinguished itself through the careful selection of well-known authors, editors, and contributors. Originally widely known as the ""Willardson and Beer"" Series, it has succeeded in publishing numerous landmark volumes and chapters. The series publishes timely, highly relevant volumes intended for long-term impact and reflecting the truly interdisciplinary nature of the field. The volumes in Semiconductors and Semimetals have been and will continue to be of great interest to physicists, chemists, materials scientists, and device engineers in academia, scien

  7. Quantum Transport in Semiconductors


    SRS i 91 4. TITLE AND SUBTITLE Quantum Transport in Semiconductors 5. FUNDING NUMBER söMtos-rizk-ooss 6. AUTHOR(S) D. K. Ferry ©fte ELECTE...OF ABSTRACT UL NSN 7540-01-280-5500 O 1 9 Standard Form 298 (Rev. 2-89) Presented by ANSI Std «9-18 298-102 Final Report Quantum Transport in... Quantum Transport in Semiconductor Devices This final report describes a program of research investigating quantum effects which become important in

  8. Introductory semiconductor device physics

    Parker, Greg


    ATOMS AND BONDINGThe Periodic TableIonic BondingCovalent BondingMetallic bondingvan der Waals BondingStart a DatabaseENERGY BANDS AND EFFECTIVE MASSSemiconductors, Insulators and MetalsSemiconductorsInsulatorsMetalsThe Concept of Effective MassCARRIER CONCENTRATIONS IN SEMICONDUCTORSDonors and AcceptorsFermi-LevelCarrier Concentration EquationsDonors and Acceptors Both PresentCONDUCTION IN SEMICONDUCTORSCarrier DriftCarrier MobilitySaturated Drift VelocityMobility Variation with TemperatureA Derivation of Ohm's LawDrift Current EquationsSemiconductor Band Diagrams with an Electric Field Presen

  9. Single semiconductor quantum dots

    Michler, Peter (ed.) [Stuttgart Univ. (Germany). Inst. fuer Halbleiteroptik und Funktionelle Grenzflaechen


    This book reviews recent advances in the exciting and rapidly growing field of semiconductor quantum dots via contributions from some of the most prominent researchers in the scientific community. Special focus is given to optical, quantum optical, and spin properties of single quantum dots due to their potential applications in devices operating with single electron spins and/or single photons. This includes single and coupled quantum dots in external fields, cavity-quantum electrodynamics, and single and entangled photon pair generation. Single Semiconductor Quantum Dots also addresses growth techniques to allow for a positioned nucleation of dots as well as applications of quantum dots in quantum information technologies. (orig.)

  10. Engineering magnetism in semiconductors

    Tomasz Dietl


    Full Text Available Transition metal doped III-V, II-VI, and group IV compounds offer an unprecedented opportunity to explore ferromagnetism in semiconductors. Because ferromagnetic spin-spin interactions are mediated by holes in the valence band, changing the Fermi level using co-doping, electric fields, or light can directly manipulate the magnetic ordering. Moreover, engineering the Fermi level position by co-doping makes it possible to modify solubility and self-compensation limits, affecting magnetic characteristics in a number of surprising ways. The Fermi energy can even control the aggregation of magnetic ions, providing a new route to self-organization of magnetic nanostructures in a semiconductor host.

  11. Liquid Crystalline Semiconductors Materials, properties and applications

    Kelly, Stephen; O'Neill, Mary


    This is an exciting stage in the development of organic electronics. It is no longer an area of purely academic interest as increasingly real applications are being developed, some of which are beginning to come on-stream. Areas that have already been commercially developed or which are under intensive development include organic light emitting diodes (for flat panel displays and solid state lighting), organic photovoltaic cells, organic thin film transistors (for smart tags and flat panel displays) and sensors. Within the family of organic electronic materials, liquid crystals are relative newcomers. The first electronically conducting liquid crystals were reported in 1988 but already a substantial literature has developed. The advantage of liquid crystalline semiconductors is that they have the easy processability of amorphous and polymeric semiconductors but they usually have higher charge carrier mobilities. Their mobilities do not reach the levels seen in crystalline organics but they circumvent all of t...

  12. Epitaxy of Semiconductors Introduction to Physical Principles

    Pohl, Udo W


    Introduction to Epitaxy provides the essential information for a comprehensive upper-level graduate course treating the crystalline growth of semiconductor heterostructures. Heteroepitaxy represents the basis of advanced electronic and optoelectronic devices today and is considered one of the top fields in materials research. The book covers the structural and electronic properties of strained epitaxial layers, the thermodynamics and kinetics of layer growth, and the description of the major growth techniques metalorganic vapor phase epitaxy, molecular beam epitaxy and liquid phase epitaxy. Cubic semiconductors, strain relaxation by misfit dislocations, strain and confinement effects on electronic states, surface structures and processes during nucleation and growth are treated in detail. The Introduction to Epitaxy requires only little knowledge on solid-state physics. Students of natural sciences, materials science and electrical engineering as well as their lecturers benefit from elementary introductions t...

  13. Megavolt nanosecond generator with semiconductor current breaker

    Bushlyakov, A I; Rukin, S N; Slovikovskij, B G; Timoshenkov, S P


    The heavy-current nanosecond generator with the pulse capacity up to 1.6 GW and output voltage of 0.5-1 MW is described. The generator contains four capacity storages, one induction storage and six solid body commutators: one thyristor, four magnetic commutators and a semiconductor current breaker on the SOS-diodes. The results of studies on the energy change-over efficiency through a semiconductor breaker by various external resistance loads as well as the results of the thermal and frequency tests are presented. It is established that selection of the optimal cooling system provides for the generator continuous mode of operation with the pulse sequence frequency from 300 Hz up to 850 Hz

  14. Metal semiconductor contacts and devices

    Cohen, Simon S; Einspruch, Norman G


    VLSI Electronics Microstructure Science, Volume 13: Metal-Semiconductor Contacts and Devices presents the physics, technology, and applications of metal-semiconductor barriers in digital integrated circuits. The emphasis is placed on the interplay among the theory, processing, and characterization techniques in the development of practical metal-semiconductor contacts and devices.This volume contains chapters that are devoted to the discussion of the physics of metal-semiconductor interfaces and its basic phenomena; fabrication procedures; and interface characterization techniques, particularl

  15. Intense terahertz excitation of semiconductors

    Ganichev, S D


    This work presents the first comprehensive treatment of high-power terahertz applications to semiconductors and low-dimensional semiconductor structures. Terahertz properties of semiconductors are in the centre of scientific activities because of the need of high-speed electronics.

  16. Amphoteric oxide semiconductors for energy conversion devices: a tutorial review.

    Singh, Kalpana; Nowotny, Janusz; Thangadurai, Venkataraman


    In this tutorial review, we discuss the defect chemistry of selected amphoteric oxide semiconductors in conjunction with their significant impact on the development of renewable and sustainable solid state energy conversion devices. The effect of electronic defect disorders in semiconductors appears to control the overall performance of several solid-state ionic devices that include oxide ion conducting solid oxide fuel cells (O-SOFCs), proton conducting solid oxide fuel cells (H-SOFCs), batteries, solar cells, and chemical (gas) sensors. Thus, the present study aims to assess the advances made in typical n- and p-type metal oxide semiconductors with respect to their use in ionic devices. The present paper briefly outlines the key challenges in the development of n- and p-type materials for various applications and also tries to present the state-of-the-art of defect disorders in technologically related semiconductors such as TiO(2), and perovskite-like and fluorite-type structure metal oxides.

  17. Electrostatic phenomena in organic semiconductors: fundamentals and implications for photovoltaics.

    D'Avino, Gabriele; Muccioli, Luca; Castet, Frédéric; Poelking, Carl; Andrienko, Denis; Soos, Zoltán G; Cornil, Jérôme; Beljonne, David


    This review summarizes the current understanding of electrostatic phenomena in ordered and disordered organic semiconductors, outlines numerical schemes developed for quantitative evaluation of electrostatic and induction contributions to ionization potentials and electron affinities of organic molecules in a solid state, and illustrates two applications of these techniques: interpretation of photoelectron spectroscopy of thin films and energetics of heterointerfaces in organic solar cells.

  18. Electrostatic phenomena in organic semiconductors: fundamentals and implications for photovoltaics

    D'Avino, Gabriele; Muccioli, Luca; Castet, Frédéric; Poelking, Carl; Andrienko, Denis; Soos, Zoltán G.; Cornil, Jérôme; Beljonne, David


    This review summarizes the current understanding of electrostatic phenomena in ordered and disordered organic semiconductors, outlines numerical schemes developed for quantitative evaluation of electrostatic and induction contributions to ionization potentials and electron affinities of organic molecules in a solid state, and illustrates two applications of these techniques: interpretation of photoelectron spectroscopy of thin films and energetics of heterointerfaces in organic solar cells.

  19. Biexcitons in semiconductor microcavities

    Borri, P.; Langbein, W.; Woggon, U.


    In this paper, the present status of the experimental study of the optical properties of biexcitons in semiconductor microcavities is reviewed. In particular, a detailed investigation of a polariton-biexciton transition in a high-quality single quantum well GaAs/AlGaAs microcavity is reported...

  20. Semiconductor Nanocrystal Photonics


    Hahn, H. Du, and T. D. Krauss, "Photoluminescence enhancement of colloidal semiconductor quantum dots embedded in a monolithic microcavity," Appl... DBRs ). The colloidal NC suspension was spun-coat into a 95-nm thick layer in the center of the cavity and then the other layers forming the top DBR

  1. Terahertz semiconductor nonlinear optics

    Turchinovich, Dmitry; Hvam, Jørn Märcher; Hoffmann, Matthias


    nonlinearity in doped semiconductors originates from the near-instantaneous heating of free electrons in the ponderomotive potential created by electric field of the THz pulse, leading to ultrafast increase of electron effective mass by intervalley scattering. Modification of effective mass in turn leads...

  2. Applied solid state science advances in materials and device research

    Wolfe, Raymond


    Applied Solid State Science: Advances in Materials and Device Research, Volume 4 covers articles on single crystal compound semiconductors and complex polycrystalline materials. The book discusses narrow gap semiconductors and solid state batteries. The text then describes the advantages of hot-pressed microcrystalline compacts of oxygen-octahedra ferroelectrics over single crystal materials, as well as heterostructure junction lasers. Solid state physicists, materials scientists, electrical engineers, and graduate students studying the subjects being discussed will find the book invaluable.

  3. Solid-state circuits

    Pridham, G J


    Solid-State Circuits provides an introduction to the theory and practice underlying solid-state circuits, laying particular emphasis on field effect transistors and integrated circuits. Topics range from construction and characteristics of semiconductor devices to rectification and power supplies, low-frequency amplifiers, sine- and square-wave oscillators, and high-frequency effects and circuits. Black-box equivalent circuits of bipolar transistors, physical equivalent circuits of bipolar transistors, and equivalent circuits of field effect transistors are also covered. This volume is divided

  4. Solid state theory

    Harrison, Walter A


    ""A well-written text . . . should find a wide readership, especially among graduate students."" - Dr. J. I. Pankove, RCA.The field of solid state theory, including crystallography, semi-conductor physics, and various applications in chemistry and electrical engineering, is highly relevant to many areas of modern science and industry. Professor Harrison's well-known text offers an excellent one-year graduate course in this active and important area of research. While presenting a broad overview of the fundamental concepts and methods of solid state physics, including the basic quantum theory o

  5. Electronic structure of semiconductor-metal-semiconductor heterostructures

    Masri, Pierre

    For the first time, we present in this article a microscopic self-consistent theory of the electronic structure of semiconductor-metal-semiconductor (SMS) heterostructures. This is done within the framework of a tight-binding approximation. We use a one-band model and a simplified two-band model to describe metal and semiconductor bulk bands, respectively. Results are given for a material-symmetrical and interface-assymetrical SMS structure: this involves the same semiconductors, but different interface polarities (anion- and cation-like interfaces). These results include metal-like states (built-in metal band) and metal-induced semiconductor-like states. The relevance of the charge neutrality condition to this feature and to the determination of the position of the SMS Fermi level is discussed. We also emphasize the confining role of interfaces, with respect to semiconductor-like states, within the semiconductor gap.

  6. Microencapsulation techniques, factors influencing encapsulation efficiency.

    Jyothi, N Venkata Naga; Prasanna, P Muthu; Sakarkar, Suhas Narayan; Prabha, K Surya; Ramaiah, P Seetha; Srawan, G Y


    Microencapsulation is one of the quality preservation techniques of sensitive substances and a method for production of materials with new valuable properties. Microencapsulation is a process of enclosing micron-sized particles in a polymeric shell. There are different techniques available for the encapsulation of drug entities. The encapsulation efficiency of the microparticle or microsphere or microcapsule depends upon different factors like concentration of the polymer, solubility of polymer in solvent, rate of solvent removal, solubility of organic solvent in water, etc. The present article provides a literature review of different microencapsulation techniques and different factors influencing the encapsulation efficiency of the microencapsulation technique.

  7. Solid state physics at ISOLDE

    Deicher, M; Wichert, T


    Radioactive atoms have been used in solid state physics and in materials science for decades. Besides their classical applications as tracers for diffusion studies, nuclear techniques such as Mossbauer spectroscopy, perturbed gamma gamma angular correlation, beta -NMR, and emission channeling make use of nuclear properties (via hyperfine interactions or emitted alpha or beta particles) to gain microscopic information on structural and dynamical properties of solids. During the last decade, the availability of many different radioactive isotopes as clean ion beams at ISOL facilities like ISOLDE/CERN has triggered a new era involving methods sensitive to the optical and electronic properties of solids, especially in the field of semiconductor physics. This overview will browse through ongoing solid state physics experiments with radioactive ion beams at ISOLDE. A wide variety of problems is under study, involving bulk properties, surfaces and interfaces in many different systems like semiconductors, superconduc...

  8. Solid State Photovoltaic Research Branch


    This report summarizes the progress of the Solid State Photovoltaic Research Branch of the Solar Energy Research Institute (SERI) from October 1, 1988, through September 30,l 1989. Six technical sections of the report cover these main areas of SERIs in-house research: Semiconductor Crystal Growth, Amorphous Silicon Research, Polycrystalline Thin Films, III-V High-Efficiency Photovoltaic Cells, Solid-State Theory, and Laser Raman and Luminescence Spectroscopy. Sections have been indexed separately for inclusion on the data base.

  9. Encapsulation of biomaterials in porous glass-like matrices prepared via an aqueous colloidal sol-gel process

    Liu, Dean-Mo; Chen, I-Wei


    The present invention provides a process for the encapsulation of biologically important proteins into transparent, porous silica matrices by an alcohol-free, aqueous, colloidal sol-gel process, and to the biological materials encapsulated thereby. The process is exemplified by studies involving encapsulated cytochrome c, catalase, myoglobin, and hemoglobin, although non-proteinaceous biomaterials, such as active DNA or RNA fragments, cells or even tissues, may also be encapsulated in accordance with the present methods. Conformation, and hence activity of the biomaterial, is successfully retained after encapsulation as demonstrated by optical characterization of the molecules, even after long-term storage. The retained conformation of the biomaterial is strongly correlated to both the rate of gelation and the subsequent drying speed of the encapsulatng matrix. Moreover, in accordance with this process, gelation is accelerated by the use of a higher colloidal solid concentration and a lower synthesis pH than conventional methods, thereby enhancing structural stability and retained conformation of the biomaterials. Thus, the invention also provides a remarkable improvement in retaining the biological activity of the encapsulated biomaterial, as compared with those involved in conventional alkoxide-based processes. It further provides new methods for the quantitative and qualitative detection of test substances that are reactive to, or catalyzed by, the active, encapsulated biological materials.

  10. Programmable Self-Assembly of DNA-Protein Hybrid Hydrogel for Enzyme Encapsulation with Enhanced Biological Stability.

    Wan, Lan; Chen, Qiaoshu; Liu, Jianbo; Yang, Xiaohai; Huang, Jin; Li, Li; Guo, Xi; Zhang, Jue; Wang, Kemin


    A DNA-protein hybrid hydrogel was constructed based on a programmable assembly approach, which served as a biomimetic physiologic matrix for efficient enzyme encapsulation. A dsDNA building block tailored with precise biotin residues was fabricated based on supersandwich hybridization, and then the addition of streptavidin triggered the formation of the DNA-protein hybrid hydrogel. The biocompatible hydrogel, which formed a flower-like porous structure that was 6.7 ± 2.1 μm in size, served as a reservoir system for enzyme encapsulation. Alcohol oxidase (AOx), which served as a representative enzyme, was encapsulated in the hybrid hydrogel using a synchronous assembly approach. The enzyme-encapsulated hydrogel was utilized to extend the duration time for ethanol removal in serum plasma and the enzyme retained 78% activity after incubation with human serum for 24 h. The DNA-protein hybrid hydrogel can mediate the intact immobilization on a streptavidin-modified and positively charged substrate, which is very beneficial to solid-phase biosensing applications. The hydrogel-encapsulated enzyme exhibited improved stability in the presence of various denaturants. For example, the encapsulated enzyme retained 60% activity after incubation at 55 °C for 30 min. The encapsulated enzyme also retains its total activity after five freeze-thaw cycles and even suspended in solution containing organic solvents.

  11. Encapsulation of cadmium selenide quantum dots using a self-assembling nanoemulsion (SANE) reduces their in vitro toxicity.

    Edmund, Anton R; Kambalapally, Swetha; Wilson, Thomas A; Nicolosi, Robert J


    Although, nanometer-scale semi-conductor quantum dots (QDs) have attracted widespread interest in medical diagnosis and treatment, many can have intrinsic toxicities, especially those composed of CdSe, associated with their elemental composition. Using our self-assembling nanoemulsion (SANE) formulations which we have previously reported to be composed of non-toxic components, i.e., such as vegetable oil, surfactant and water, we hypothesized that their appropriate utilization would reduce the toxicity of QDs by encapsulating the CdSe QDs in our (SANE) system using a modified phase-inversion temperature (PIT) method. SANE encapsulation of the QDs did not alter their emission wavelength of 600nm which remained unchanged during the encapsulation process. In contrast, zeta potential of encapsulated QDs was reduced from -30 to -6.59 mV, which we have previously reported to be associated with beneficial properties (increased bioavailability and efficacy) for SANE-encapsulated bioactives such as pharmaceuticals. Relative to the untreated controls, the viability of HeLa cells exposed for 48 h to un-encapsulated CdSe QDs at a concentration of 115 μg/mL was 22.7±1.7% (p<0.05). In contrast, the percentage of viable HeLa cells following exposure to SANE-encapsulated CdSe QDs at the same concentration was 91.6±3.5% (p<0.05) or a 307% increase in the number of viable cells (p<0.05). When the dose of CdSe QDs was increased to 230 μg/mL, the percentage of viable HeLa cells after exposure to the un-encapsulated CdSe QDs was 16.1±1.3% compared to controls (p<0.05). In contrast, at the same increased concentration (230 μg/mL) of un-encapsulated CdSe QDs, the percentage of viable HeLa cells following exposure to SANE-encapsulated CdSe QDs was 87.9±3.3% relative to controls (p<0.05) or a 448% increase in the number of viable cells (p<0.05). Exposure of HeLa cells to a nanoblank, (nanoemulsion without QDs), showed no significant effect on cell viability (97.2±2.5%) compared to

  12. Encapsulation of isohexenylnaphthazarins in cyclodextrins.

    Assimopoulou, A N; Papageorgiou, V P


    Naturally occurring isohexenylnaphthazarins (IHN), such as Alkannin, Shikonin (A/S) and their derivatives, are potent pharmaceutical substances with a wide spectrum of biological activity. In the present study, inclusion complexes of alkannin and shikonin commercial samples and IHN derivatives in the form of an oily extract of Alkanna tinctoria roots were formed with beta-cyclodextrin (CD) and beta-HPCD. These complexes were investigated to evaluate the effect of complexation on their aqueous solubility, decoloration, and also the percentage of polymeric A/S and IHN derivatives enclosed in the CDs cavity, since these decrease the active monomeric IHN. Both beta-CD and beta-HPCD increased the aqueous solubility of A/S and IHN derivatives and thus inclusion complexes can be used as drug delivery systems for A/S in both internal (capsules, tablets) and external hydrophilic pharmaceutical and cosmetic preparations (creams, gels, sprays) with enhanced bioavailability. The inclusion complexes formed had a pale purple colour, contributing to the partial decoloration of the A/S and thus of the fi nal pharmaceutical preparations. Finally, CDs selectively included more monomeric and less polymeric IHN, compared with the initial each time sample that is encapsulated; thus inclusion complexes may present enhanced biological activity.

  13. Lipid encapsulated phenolic compounds by fluidization

    Phenolic compounds exhibit antioxidant and antimicrobial activities with applications as functional food and feed additives. Ferulic acid, a phenolic compound present in grain crops and lignocellulose biomass, was encapsulated with saturated triglycerides using a laboratory fluidizer. Stability of t...

  14. Ultrasound-induced encapsulated microbubble phenomena

    Postema, Michiel; Wamel, van Annemieke; Lancée, Charles T.; Jong, de Nico


    When encapsulated microbubbles are subjected to high-amplitude ultrasound, the following phenomena have been reported: oscillation, translation, coalescence, fragmentation, sonic cracking and jetting. In this paper, we explain these phenomena, based on theories that were validated for relatively big

  15. Review of potential processing techniques for the encapsulation of wastes in thermoplastic polymers

    Patel, B.R.; Lageraaen, P.R.; Kalb, P.D.


    Thermoplastic encapsulation has been extensively studied at Brookhaven National Laboratory`s (BNL) Environmental and Waste Technology Center (EWTC) as a waste encapsulation technology applicable to a wide range of waste types including radioactive, hazardous and mixed wastes. Encapsulation involves processing thermoplastic and waste materials into a waste form product by heating and mixing both materials into a homogeneous molten mixture. Cooling of the melt results in a solid monolithic waste form in which contaminants have been completely surrounded by a polymer matrix. Heating and mixing requirements for successful waste encapsulation can be met using proven technologies available in various types of commercial equipment. Processing techniques for thermoplastic materials, such as low density polyethylene (LDPE), are well established within the plastics industry. The majority of commercial polymer processing is accomplished using extruders, mixers or a combination of these technologies. Extruders and mixers are available in a broad range of designs and are used during the manufacture of consumer and commercial products as well as for compounding applications. Compounding which refers to mixing additives such as stabilizers and/or colorants with polymers, is analogous to thermoplastic encapsulation. Several processing technologies were investigated for their potential application in encapsulating residual sorbent waste in selected thermoplastic polymers, including single-screw extruders, twin-screw extruders, continuous mixers, batch mixers as well as other less conventional devices. Each was evaluated based on operational ease, quality control, waste handling capabilities as well as degree of waste pretreatment required. Based on literature review, this report provides a description of polymer processing technologies, a discussion of the merits and limitations of each and an evaluation of their applicability to the encapsulation of sorbent wastes.

  16. Sclerosing encapsulating peritonitis: a case report

    Candido, Paula de Castro Menezes; Werner, Andrea de Freitas; Pereira, Izabela Machado Flores; Matos, Breno Assuncao; Pfeilsticker, Rudolf Moreira; Silva Filho, Raul, E-mail: [Hospital Felicio Rocho, Belo Horizonte, MG (Brazil)


    Sclerosing encapsulating peritonitis, a rare cause of bowel obstruction, was described as a complication associated with peritoneal dialysis which is much feared because of its severity. The authors report a case where radiological findings in association with clinical symptoms have allowed for a noninvasive diagnosis of sclerosing encapsulating peritonitis, emphasizing the high sensitivity and specificity of computed tomography to demonstrate the characteristic findings of such a condition. (author)

  17. Encapsulated Thermoelectric Modules for Advanced Thermoelectric Systems

    Kambe, Mitsuru; Jinushi, Takahiro; Ishijima, Zenzo


    An encapsulated thermoelectric (TE) module consists of a vacuum-tight stainless-steel container in which an SiGe or BiTe TE module is encapsulated. This construction enables maximum performance and durability because: the thermal expansion mismatch between the hot and cold sides of the container can be accommodated by a sliding sheet in the container; the TE module inside is always kept in a vacuum environment, therefore no oxidation can occur; and the pressure difference between the inside and outside of the container reduces thermal contact resistance inside the container. Our encapsulated SiGe module features higher operating temperature—up to 650°C for both hot and cold sides. Other high-temperature modules and conventional BiTe modules, including both-sides and one-side skeleton types, have been encapsulated. Several variants of the encapsulated module are available. Encapsulated thermoelectric modules with integrated coolers contain cooling panels through which water can pass. If the module hot side is heated by a radiating heat source (radiation coupling) or convection of a hot gas or fluid (convection coupling), no pressing force on the module is necessary. It therefore features minimum contact resistance with the cooling duct, because no pressure is applied, maximum TE power, and minimum installation cost. Another, larger, variant is a quadruple flexible container in which four modules (each of maximum size 40 mm × 40 mm) are encapsulated. These encapsulated modules were used in a powder metallurgy furnace and were in use for more than 3000 h. Application to cryogenic temperatures simulating the liquid nitrogen gas vaporizer has been also attempted.

  18. Encapsulation and Fluorescence of the Functional Supramolecular Material Between MCM-41 and Rh6G


    @@ Molecular sieves encapsulated organic dyes and metal chelates have been reviewed[1],the luminescent behavior of some organic compounds in molecular sieves has also been studied[2,3].Rh6G (Rhodamine 6G) is one kind of organic dye which is widely used in many fields such as optics,spectroscopy and laser techniques.It has a high stability and an efficiency quantum yield as an excellent fluorescent compound.The mesoporous molecular sieve MCM-41 possesses advantageous absorption property.It is conceivable that studies on the encapsulation of the fluorescent organic compounds in MCM-41 may give a new impetus to working on solid-state luminescence.We have reported the encapsulation of rhodamine B into MCM-41 and its fluorescent property[4].In this paper,the encapsulation and the fluorescence of the functional supramolecular material of MCM-41,which was synthesized by means of MRM(Microwave radiation method),encapsulated Rh6G have been reported.

  19. Materials for diode pumped solid state lasers

    Chase, L. L.; Davis, L. E.; Krupke, W. F.; Payne, S. A.


    The advantages of semiconductor diode lasers and laser arrays as pump sources for solid state lasers are reviewed. The properties that are desirable in solid state laser media for various diode pumping applications are discussed, and the characteristics of several promising media are summarized.

  20. Architectures for Improved Organic Semiconductor Devices

    Beck, Jonathan H.

    Advancements in the microelectronics industry have brought increasing performance and decreasing prices to a wide range of users. Conventional silicon-based electronics have followed Moore's law to provide an ever-increasing integrated circuit transistor density, which drives processing power, solid-state memory density, and sensor technologies. As shrinking conventional integrated circuits became more challenging, researchers began exploring electronics with the potential to penetrate new applications with a low price of entry: "Electronics everywhere." The new generation of electronics is thin, light, flexible, and inexpensive. Organic electronics are part of the new generation of thin-film electronics, relying on the synthetic flexibility of carbon molecules to create organic semiconductors, absorbers, and emitters which perform useful tasks. Organic electronics can be fabricated with low energy input on a variety of novel substrates, including inexpensive plastic sheets. The potential ease of synthesis and fabrication of organic-based devices means that organic electronics can be made at very low cost. Successfully demonstrated organic semiconductor devices include photovoltaics, photodetectors, transistors, and light emitting diodes. Several challenges that face organic semiconductor devices are low performance relative to conventional devices, long-term device stability, and development of new organic-compatible processes and materials. While the absorption and emission performance of organic materials in photovoltaics and light emitting diodes is extraordinarily high for thin films, the charge conduction mobilities are generally low. Building highly efficient devices with low-mobility materials is one challenge. Many organic semiconductor films are unstable during fabrication, storage, and operation due to reactions with water, oxygen and hydroxide. A final challenge facing organic electronics is the need for new processes and materials for electrodes

  1. Semiconductor Photocatalysis for Chemoselective Radical Coupling Reactions.

    Kisch, Horst


    transfers with unsaturated donor and acceptor substrates. The radicals diffuse in a solid-solute-surface layer to undergo chemo- and stereoselective C-C and C-N bond formation. Thus, the semiconductor photocatalyst functions like an artificial leaf. Since several minerals are known to have semiconductor properties, solar photocatalysis may be also relevant for prebiotic and environmental chemistry.

  2. Protein encapsulation in polymeric microneedles by photolithography

    Kochhar JS


    Full Text Available Jaspreet Singh Kochhar,1 Shui Zou,2 Sui Yung Chan,1 Lifeng Kang11Department of Pharmacy, 2Department of Chemistry, National University of Singapore, SingaporeBackground: Recent interest in biocompatible polymeric microneedles for the delivery of biomolecules has propelled considerable interest in fabrication of microneedles. It is important that the fabrication process is feasible for drug encapsulation and compatible with the stability of the drug in question. Moreover, drug encapsulation may offer the advantage of higher drug loading compared with other technologies, such as drug coating.Methods and results: In this study, we encapsulated a model protein drug, namely, bovine serum albumin, in polymeric microneedles by photolithography. Drug distribution within the microneedle array was found to be uniform. The encapsulated protein retained its primary, secondary, and tertiary structural characteristics. In vitro release of the encapsulated protein showed that almost all of the drug was released into phosphate buffered saline within 6 hours. The in vitro permeation profile of encapsulated bovine serum albumin through rat skin was also tested and shown to resemble the in vitro release profile, with an initial release burst followed by a slow release phase. The cytotoxicity of the microneedles without bovine serum albumin was tested in three different cell lines. High cell viabilities were observed, demonstrating the innocuous nature of the microneedles.Conclusion: The microneedle array can potentially serve as a useful drug carrier for proteins, peptides, and vaccines.Keywords: poly (ethylene glycol diacrylate, microneedles, protein stability, photolithography, biocompatibility

  3. Solid-state devices and applications

    Lewis, Rhys


    Solid-State Devices and Applications is an introduction to the solid-state theory and its devices and applications. The book also presents a summary of all major solid-state devices available, their theory, manufacture, and main applications. The text is divided into three sections. The first part deals with the semiconductor theory and discusses the fundamentals of semiconductors; the kinds of diodes and techniques in their manufacture; the types and modes of operation of bipolar transistors; and the basic principles of unipolar transistors and their difference with bipolar transistors. The s

  4. Comparison of the Acidity of Heteropolyacids Encapsulated in or Impregnated on SBA-15

    Pinto Teresa


    Full Text Available Heteropolyacids (HPA immobilized onto SBA-15 silica were prepared by two different ways using either impregnation or encapsulation methodologies. Two Keggin-type HPA, H3PW12O40 and H4SiW12O40 were considered in this study. The resulting hybrid materials were fully characterized by N2 adsorption-desorption isotherms, XRD, FT-IR, Raman, diffuse reflectance UV-Vis spectroscopies and 31P MAS NMR. All characterization methods showed that at room temperature the catalysts contained well-dispersed and intact Keggin units throughout the solid. The catalytic activity of these solids was investigated in the isomerization of n-hexane. The impregnated and encapsulated phosphotungstic catalysts performed similarly in catalysis showing that the amount of active sites was nearly the same in both catalysts. On the contrary, the tungstosilicic encapsulated material was completely inactive while its impregnated counterpart was even more active than the phosphotungstic derived catalysts. The acidity of the solids was measured by various methods: microcalorimetry of ammonia adsorption, ammonia desorption followed by Temperature Programmed Desorption (TPD and DRIFT/GC-MS and pyridine adsorption followed by infrared spectroscopy. Only pyridine adsorption and ammonia desorption followed by DRIFT/GC-MS agreed with the catalytic data. Ammonia adsorption followed by microcalorimetry was not able to differentiate between the four catalysts while the TPD experiments led to unreliable results, as not only the evolved ammonia but also other molecules such as water were taken into account in the measurements. The behavior difference between the encapsulated silico- and phosphotungstic acids was explained by a more pronounced encapsulation in the case of silicon.

  5. Stretchable Organic Semiconductor Devices.

    Qian, Yan; Zhang, Xinwen; Xie, Linghai; Qi, Dianpeng; Chandran, Bevita K; Chen, Xiaodong; Huang, Wei


    Stretchable electronics are essential for the development of intensely packed collapsible and portable electronics, wearable electronics, epidermal and bioimplanted electronics, 3D surface compliable devices, bionics, prosthesis, and robotics. However, most stretchable devices are currently based on inorganic electronics, whose high cost of fabrication and limited processing area make it difficult to produce inexpensive, large-area devices. Therefore, organic stretchable electronics are highly attractive due to many advantages over their inorganic counterparts, such as their light weight, flexibility, low cost and large-area solution-processing, the reproducible semiconductor resources, and the easy tuning of their properties via molecular tailoring. Among them, stretchable organic semiconductor devices have become a hot and fast-growing research field, in which great advances have been made in recent years. These fantastic advances are summarized here, focusing on stretchable organic field-effect transistors, light-emitting devices, solar cells, and memory devices.

  6. Single frequency semiconductor lasers

    Fang, Zujie; Chen, Gaoting; Qu, Ronghui


    This book systematically introduces the single frequency semiconductor laser, which is widely used in many vital advanced technologies, such as the laser cooling of atoms and atomic clock, high-precision measurements and spectroscopy, coherent optical communications, and advanced optical sensors. It presents both the fundamentals and characteristics of semiconductor lasers, including basic F-P structure and monolithic integrated structures; interprets laser noises and their measurements; and explains mechanisms and technologies relating to the main aspects of single frequency lasers, including external cavity lasers, frequency stabilization technologies, frequency sweeping, optical phase locked loops, and so on. It paints a clear, physical picture of related technologies and reviews new developments in the field as well. It will be a useful reference to graduate students, researchers, and engineers in the field.

  7. Three dimensional strained semiconductors

    Voss, Lars; Conway, Adam; Nikolic, Rebecca J.; Leao, Cedric Rocha; Shao, Qinghui


    In one embodiment, an apparatus includes a three dimensional structure comprising a semiconductor material, and at least one thin film in contact with at least one exterior surface of the three dimensional structure for inducing a strain in the structure, the thin film being characterized as providing at least one of: an induced strain of at least 0.05%, and an induced strain in at least 5% of a volume of the three dimensional structure. In another embodiment, a method includes forming a three dimensional structure comprising a semiconductor material, and depositing at least one thin film on at least one surface of the three dimensional structure for inducing a strain in the structure, the thin film being characterized as providing at least one of: an induced strain of at least 0.05%, and an induced strain in at least 5% of a volume of the structure.

  8. Effective electron mass in low-dimensional semiconductors

    Bhattacharya, Sitangshu [Indian Institute of Science, Bangalore (India). Nano Scale Device Research Lab.; Ghatak, Kamakhya Prasad [National Institute of Technology, Agartala, Tripura West (India). Dept. of Electronics and Communication Engineering


    Provides a treatment of the effective electron mass in nanodevices. Explains changes of the band structure of optoelectronic semiconductors by intense electric fields and light waves. Gives insight into the electronic behavior in doped semiconductors and their nanostructures. Supports tuition by 200 open problems and questions. This book deals with the Effective Electron Mass (EEM) in low dimensional semiconductors. The materials considered are quantum confined non-linear optical, III-V, II-VI, GaP, Ge, PtSb2, zero-gap, stressed, Bismuth, carbon nanotubes, GaSb, IV-VI, Te, II-V, Bi2Te3, Sb, III-V, II-VI, IV-VI semiconductors and quantized III-V, II-VI, IV-VI and HgTe/CdTe superlattices with graded interfaces and effective mass superlattices. The presence of intense electric field and the light waves change the band structure of optoelectronic semiconductors in fundamental ways, which have also been incorporated in the study of the EEM in quantized structures of optoelectronic compounds that control the studies of the quantum effect devices under strong fields. The importance of measurement of band gap in optoelectronic materials under strong electric field and external photo excitation has also been discussed in this context. The influence of crossed electric and quantizing magnetic fields on the EEM and the EEM in heavily doped semiconductors and their nanostructures is discussed. This book contains 200 open research problems which form the integral part of the text and are useful for both Ph. D aspirants and researchers in the fields of solid-state sciences, materials science, nanoscience and technology and allied fields in addition to the graduate courses in modern semiconductor nanostructures. The book is written for post graduate students, researchers and engineers, professionals in the fields of solid state sciences, materials science, nanoscience and technology, nanostructured materials and condensed matter physics.

  9. Encapsulation of tea tree oil by amorphous beta-cyclodextrin powder.

    Shrestha, Meena; Ho, Thao M; Bhandari, Bhesh R


    An innovative method to encapsulate tea tree oil (TTO) by direct complexation with solid amorphous beta-cyclodextrin (β-CD) was investigated. A β-CD to TTO ratio of 90.5:9.5 (104.9mg TTO/g β-CD) was used in all complexation methods. The encapsulation was performed by direct mixing, and direct mixing was followed by the addition of water (13-17% moisture content, MC) or absolute ethanol (1:1, 1:2, 1:3 and 1:4 TTO:ethanol). The direct mixing method complexed the lowest amount of TTO (60.77mg TTO/g β-CD). Powder recrystallized using 17% MC included 99.63mg of TTO/g β-CD. The addition of ethanol at 1:2 and 1:3 TTO:ethanol ratios resulted in the inclusion of 94.3 and 98.45mg of TTO/g β-CD respectively, which was similar to that of TTO encapsulated in the conventional paste method (95.56mg TTO/g β-CD), suggesting an effective solid encapsulation method. The XRD and DSC results indicated that the amorphous TTO-β-CD complex was crystallized by the addition of water and ethanol.

  10. Hollow Alveolus-Like Nanovesicle Assembly with Metal-Encapsulated Hollow Zeolite Nanocrystals.

    Dai, Chengyi; Zhang, Anfeng; Liu, Min; Gu, Lin; Guo, Xinwen; Song, Chunshan


    Inspired by the vesicular structure of alveolus which has a porous nanovesicle structure facilitating the transport of oxygen and carbon dioxide, we designed a hollow nanovesicle assembly with metal-encapsulated hollow zeolite that would enhance diffusion of reactants/products and inhibit sintering and leaching of active metals. This zeolitic nanovesicle has been successfully synthesized by a strategy which involves a one-pot hydrothermal synthesis of hollow assembly of metal-containing solid zeolite crystals without a structural template and a selective desilication-recrystallization accompanied by leaching-hydrolysis to convert the metal-containing solid crystals into metal-encapsulated hollow crystals. We demonstrate the strategy in synthesizing a hollow nanovesicle assembly of Fe2O3-encapsulated hollow crystals of ZSM-5 zeolite. This material possesses a microporous (0.4-0.6 nm) wall of hollow crystals and a mesoporous (5-17 nm) shell of nanovesicle with macropores (about 350 nm) in the core. This hierarchical structure enables excellent Fe2O3 dispersion (3-4 nm) and resistance to sintering even at 800 °C; facilitates the transport of reactant/products; and exhibits superior activity and resistance to leaching in phenol degradation. Hollow nanovesicle assembly of Fe-Pt bimetal-encapsulated hollow ZSM-5 crystals was also prepared.

  11. Semiconductors for organic transistors

    Antonio Facchetti


    Organic molecules/polymers with a π-conjugated (hetero)aromatic backbone are capable of transporting charge and interact efficiently with light. Therefore, these systems can act as semiconductors in opto-electronic devices similar to inorganic materials. However, organic chemistry offers tools for tailoring materials' functional properties via modifications of the molecular/monomeric units, opening new possibilities for inexpensive device manufacturing. This article reviews the fundamental as...

  12. Doping of organic semiconductors

    Luessem, B.; Riede, M.; Leo, K. [Institut fuer Angewandte Photophysik, TU Dresden (Germany)


    The understanding and applications of organic semiconductors have shown remarkable progress in recent years. This material class has been developed from being a lab curiosity to the basis of first successful products as small organic LED (OLED) displays; other areas of application such as OLED lighting and organic photovoltaics are on the verge of broad commercialization. Organic semiconductors are superior to inorganic ones for low-cost and large-area optoelectronics due to their flexibility, easy deposition, and broad variety, making tailor-made materials possible. However, electrical doping of organic semiconductors, i.e. the controlled adjustment of Fermi level that has been extremely important to the success of inorganic semiconductors, is still in its infancy. This review will discuss recent work on both fundamental principles and applications of doping, focused primarily to doping of evaporated organic layers with molecular dopants. Recently, both p- and n-type molecular dopants have been developed that lead to efficient and stable doping of organic thin films. Due to doping, the conductivity of the doped layers increases several orders of magnitude and allows for quasi-Ohmic contacts between organic layers and metal electrodes. Besides reducing voltage losses, doping thus also gives design freedom in terms of transport layer thickness and electrode choice. The use of doping in applications like OLEDs and organic solar cells is highlighted in this review. Overall, controlled molecular doping can be considered as key enabling technology for many different organic device types that can lead to significant improvements in efficiencies and lifetimes. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Tunable Infrared Semiconductor Lasers


    Lett. 81, 406-408 (2002). [20] M. Ito and T. Kimura, “Oscillation properties of AlGaAs DH Lasrs with an external grating,” IEEE J. Quant. Elec- tron...tuning range has been demonstrated on a large area index-coupled, optically pumped mid-infrared type-II semiconductor distributed feedback (DFB) laser...lithography (IL) technique is used to pattern this chirped grating with two coherent spherical waves. A new grating fabrication optical arrangement

  14. Semiconductor Ion Implanters

    MacKinnon, Barry A.; Ruffell, John P.


    In 1953 the Raytheon CK722 transistor was priced at 7.60. Based upon this, an Intel Xeon Quad Core processor containing 820,000,000 transistors should list at 6.2 billion! Particle accelerator technology plays an important part in the remarkable story of why that Intel product can be purchased today for a few hundred dollars. Most people of the mid twentieth century would be astonished at the ubiquity of semiconductors in the products we now buy and use every day. Though relatively expensive in the nineteen fifties they now exist in a wide range of items from high-end multicore microprocessors like the Intel product to disposable items containing `only' hundreds or thousands like RFID chips and talking greeting cards. This historical development has been fueled by continuous advancement of the several individual technologies involved in the production of semiconductor devices including Ion Implantation and the charged particle beamlines at the heart of implant machines. In the course of its 40 year development, the worldwide implanter industry has reached annual sales levels around 2B, installed thousands of dedicated machines and directly employs thousands of workers. It represents in all these measures, as much and possibly more than any other industrial application of particle accelerator technology. This presentation discusses the history of implanter development. It touches on some of the people involved and on some of the developmental changes and challenges imposed as the requirements of the semiconductor industry evolved.

  15. Encapsulation of Enzymes and Peptides

    Meesters, Gabrie M. H.

    A large part of formulated peptides and proteins, e.g., enzymes used as food ingredients, are formulated in a liquid form. Often, they are dissolved in water to which glycerol or sorbitol is added to reduce the water activity of the liquid, thus reducing the change of microbial growth. Still, there are reasons to formulate them in a solid form. Often, these reasons are stability, since a dry formulation is often much better than liquid formulations, and less transportation cost, since less mass is transported if one gets rid of the liquid; however, most of the times, the reason is that the product is mixed with a solid powder. Here, a liquid addition would lead to lump formation.

  16. Photoelectrochemistry of Semiconductor Nanowire Arrays

    Mallouk, Thomas E; Redwing, Joan M


    This project supported research on the growth and photoelectrochemical characterization of semiconductor nanowire arrays, and on the development of catalytic materials for visible light water splitting to produce hydrogen and oxygen. Silicon nanowires were grown in the pores of anodic aluminum oxide films by the vapor-liquid-solid technique and were characterized electrochemically. Because adventitious doping from the membrane led to high dark currents, silicon nanowire arrays were then grown on silicon substrates. The dependence of the dark current and photovoltage on preparation techniques, wire diameter, and defect density was studied for both p-silicon and p-indium phosphide nanowire arrays. The open circuit photovoltage of liquid junction cells increased with increasing wire diameter, reaching 350 mV for micron-diameter silicon wires. Liquid junction and radial p-n junction solar cells were fabricated from silicon nano- and microwire arrays and tested. Iridium oxide cluster catalysts stabilized by bidentate malonate and succinate ligands were also made and studied for the water oxidation reaction. Highlights of this project included the first papers on silicon and indium phosphide nanowire solar cells, and a new procedure for making ligand-stabilized water oxidation catalysts that can be covalently linked to molecular photosensitizers or electrode surfaces.

  17. Solution-phase Synthesis of One-dimensional Semiconductor Nanostructures

    Jianfeng YE; Limin QI


    The synthesis of one-dimensional (1D) semiconductor nanostructures has been studied intensively for a wide range of materials due to their unique structural and physical properties and promising potential for future technological applications. Among various strategies for synthesizing 1D semiconductor nanostructures, solution-phase synthetic routes are advantageous in terms of cost, throughput, modulation of composition, and the potential for large-scale and environmentally benign production. This article gives a concise review on the recent developments in the solution-phase synthesis of 1D semiconductor nanostructures of different compositions, sizes, shapes, and architectures. We first introduce several typical solution-phase synthetic routes based on controlled precipitation from homogeneous solutions, including hydrothermal/solvothermal process, solution-liquid-solid (SLS) process, high-temperature organic-solution process, and low-temperature aqueous-solution process. Subsequently, we discuss two solution-phase synthetic strategies involving solid templates or substrates, such as the chemical transformation of 1D sacrificial templates and the oriented growth of 1D nanostructure arrays on solid substrates. Finally, prospects of the solution-phase approaches to 1D semiconductor nanostructures will be briefly discussed.

  18. Low temperature production of large-grain polycrystalline semiconductors

    Naseem, Hameed A. (Fayetteville, AR); Albarghouti, Marwan (Loudonville, NY)


    An oxide or nitride layer is provided on an amorphous semiconductor layer prior to performing metal-induced crystallization of the semiconductor layer. The oxide or nitride layer facilitates conversion of the amorphous material into large grain polycrystalline material. Hence, a native silicon dioxide layer provided on hydrogenated amorphous silicon (a-Si:H), followed by deposited Al permits induced crystallization at temperatures far below the solid phase crystallization temperature of a-Si. Solar cells and thin film transistors can be prepared using this method.

  19. Liquid-Phase Epitaxy Effective Encapsulation of Lanthanide Coordination Compounds into MOF Film with Homogeneous and Tunable White-Light Emission.

    Gu, Zhi-Gang; Chen, Zheng; Fu, Wen-Qiang; Wang, Fei; Zhang, Jian


    As a new family of hybrid inorganic-organic materials with large porosity, metal-organic frameworks (MOFs) have received attractive attention recently on encapsulating functional guest species. Although the encapsulation of luminescent guest into bulk MOFs can tune the luminescent property, the powder composite materials are limited to the application in optical sensors and devices. In the present work, we use a modified liquid-phase epitaxial (LPE) pump method for the fabrication of lanthanide coordination compounds (LCCs)-encapsulated MOF thin film on substrate with high encapsulation efficiency. The resultant composite film reveals an oriented and homogeneous composite film, in which a white light emission by tuning the LCCs of red, blue and green emission can be obtained. This strategy may open new perspectives for developing high-encapsulation-efficiency, oriented, and homogeneous solid-state lighting composite films in the application of optical sensors and devices.

  20. Highly emitting near-infrared lanthanide "encapsulated sandwich" metallacrown complexes with excitation shifted toward lower energy.

    Trivedi, Evan R; Eliseeva, Svetlana V; Jankolovits, Joseph; Olmstead, Marilyn M; Petoud, Stéphane; Pecoraro, Vincent L


    Near-infrared (NIR) luminescent lanthanide complexes hold great promise for practical applications, as their optical properties have several complementary advantages over organic fluorophores and semiconductor nanoparticles. The fundamental challenge for lanthanide luminescence is their sensitization through suitable chromophores. The use of the metallacrown (MC) motif is an innovative strategy to arrange several organic sensitizers at a well-controlled distance from a lanthanide cation. Herein we report a series of lanthanide “encapsulated sandwich” MC complexes of the form Ln3+ [12-MC(Zn(II),quinHA)-4]2[24-MC(Zn(II),quinHA)-8] (Ln3+ [Zn(II)MC(quinHA)]) in which the MC framework is formed by the self-assembly of Zn2+ ions and tetradentate chromophoric ligands based on quinaldichydroxamic acid (quinHA). A first-generation of luminescent MCs was presented previously but was limited due to excitation wavelengths in the UV. We report here that through the design of the chromophore of the MC assembly, we have significantly shifted the absorption wavelength toward lower energy (450 nm). In addition to this near-visible inter- and/or intraligand charge transfer absorption, Ln3+ [Zn(II)MC(quinHA)] exhibits remarkably high quantum yields, long luminescence lifetimes (CD3OD; Yb3+, QLn(L) = 2.88(2)%, τobs = 150.7(2) μs; Nd3+, QLn(L) = 1.35(1)%, τobs = 4.11(3) μs; Er3+, QLn(L) = 3.60(6)·10–2%, τobs = 11.40(3) μs), and excellent photostability. Quantum yields of Nd3+ and Er3+ MCs in the solid state and in deuterated solvents, upon excitation at low energy, are the highest values among NIR-emitting lanthanide complexes containing C–H bonds. The versatility of the MC strategy allows modifications in the excitation wavelength and absorptivity through the appropriate design of the ligand sensitizer, providing a highly efficient platform with tunable properties.

  1. Cytokine production induced by non-encapsulated and encapsulated Porphyromonas gingivalis strains

    Kunnen, A.; Dekker, D.C.; van Pampus, M.G.; Harmsen, H.J.; Aarnoudse, J.G.; Abbas, F.; Faas, M.M.


    Objective: Although the exact reason is not known, encapsulated gram-negative Porphyromonas gingivalis strains are more virulent than non-encapsulated strains. Since difference in virulence properties may be due to difference in cytokine production following recognition of the bacteria or their prod

  2. Organic solid-state lasers

    Forget, Sébastien


    Organic lasers are broadly tunable coherent sources, potentially compact, convenient and manufactured at low-costs. Appeared in the mid 60’s as solid-state alternatives for liquid dye lasers, they recently gained a new dimension after the demonstration of organic semiconductor lasers in the 90's. More recently, new perspectives appeared at the nanoscale, with organic polariton and surface plasmon lasers. After a brief reminder to laser physics, a first chapter exposes what makes organic solid-state organic lasers specific. The laser architectures used in organic lasers are then reviewed, with a state-of-the-art review of the performances of devices with regard to output power, threshold, lifetime, beam quality etc. A survey of the recent trends in the field is given, highlighting the latest developments with a special focus on the challenges remaining for achieving direct electrical pumping of organic semiconductor lasers. A last chapter covers the applications of organic solid-state lasers.

  3. Encapsulation of antioxidants in gastrointestinal-resistant nanoparticulate carriers.

    Souto, Eliana B; Severino, Patrícia; Basso, Rafael; Santana, Maria Helena A


    Reactive oxygen species (ROS) are known to cause several human pathologies. For this reason, antioxidants have gained utmost importance because of their potential as prophylactic and therapeutic agents in many diseases. Examples of their application include their use in diabetic patients, as aging drugs, in cancer diseases, Parkinson's, Alzheimer's, autoimmune disorders, and also in inflammation. Antioxidants have limited absorption profiles, therefore low bioavailability and low concentrations at the target site. Efforts have been done towards loading antioxidant molecules in advanced nanoparticulate carriers, e.g., liposomes, polymeric nanoparticles, solid lipid nanoparticles, self-emulsifying drug delivery system. Examples of -successful achievements include the encapsulation of drugs and other active ingredients, e.g., coenzyme Q10, vitamin E and vitamin A, resveratrol and polyphenols, curcumin, lycopene, silymarin, and superoxide dismutase. This review focuses on the comprehensive analysis of using nanoparticulate carriers for loading these molecules for oral administration.

  4. Tungsten-encapsulated gadolinium nanoislands with enhanced magnetocaloric response

    Logan, J. M.; Rosenmann, D.; Sangpo, T.; Holt, M. V.; Fuesz, P.; McNulty, I.


    We report a method for growing chemically pure, oxide-free, air-stable Gd nanoislands with enhanced magnetic properties. These nanoislands are grown by solid-state dewetting and are fully encapsulated in tungsten such that they remain stable in ambient environments. They display good crystalline properties with hexagonally close-packed crystal structure and strong preferential orientation. We show that the choice of substrate strongly affects their shape, crystal orientation, and magnetic properties. The temperature-dependent magnetic coercivity and remanence of the Gd islands can vary by as much as a factor of three depending on the substrate used. The magnetocaloric properties of Gd islands grown on a sapphire substrate exceed those of high-quality Gd thin films.

  5. Method of passivating semiconductor surfaces

    Wanlass, Mark W.


    A method of passivating Group III-V or II-VI semiconductor compound surfaces. The method includes selecting a passivating material having a lattice constant substantially mismatched to the lattice constant of the semiconductor compound. The passivating material is then grown as an ultrathin layer of passivating material on the surface of the Group III-V or II-VI semiconductor compound. The passivating material is grown to a thickness sufficient to maintain a coherent interface between the ultrathin passivating material and the semiconductor compound. In addition, a device formed from such method is also disclosed.

  6. Electrodes for Semiconductor Gas Sensors.

    Lee, Sung Pil


    The electrodes of semiconductor gas sensors are important in characterizing sensors based on their sensitivity, selectivity, reversibility, response time, and long-term stability. The types and materials of electrodes used for semiconductor gas sensors are analyzed. In addition, the effect of interfacial zones and surface states of electrode-semiconductor interfaces on their characteristics is studied. This study describes that the gas interaction mechanism of the electrode-semiconductor interfaces should take into account the interfacial zone, surface states, image force, and tunneling effect.

  7. Poly(lactide-co-glycolide) encapsulated hydroxyapatite microspheres for sustained release of doxycycline

    Wang Xiaoyun [School of Pharmacy, Shenyang Pharmaceutical University, 103, Wenhua Road, Shenyang 110016 (China); Department of Pharmacy, Shandong Drug and Food Vocational College, Science and Technology Town, Hightech Industrial Development Zone, Weihai 264210 (China); Xu Hui; Zhao Yanqiu [School of Pharmacy, Shenyang Pharmaceutical University, 103, Wenhua Road, Shenyang 110016 (China); Wang Shaoning, E-mail: [School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, 103, Wenhua Road, Shenyang 110016 (China); Abe, Hiroya; Naito, Makio [Joining and Welding Research Institute, Osaka University, 11-1, Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Liu Yanli [School of Pharmacy, Shenyang Pharmaceutical University, 103, Wenhua Road, Shenyang 110016 (China); Wang Guoqing [School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, 103, Wenhua Road, Shenyang 110016 (China)


    Highlights: Black-Right-Pointing-Pointer PLGA encapsulated HAP-MSs were used for the sustained delivery of Doxycycline (Doxy, a broad spectrum tetracycline antibiotic). Black-Right-Pointing-Pointer Sustained Doxy release without obvious burst was observed. Black-Right-Pointing-Pointer Mechanism of the sustained Doxy release was illustrated. Black-Right-Pointing-Pointer Sustained Doxy release character in vivo was also obtained, the plasma Doxy levels were relatively lower and steady compared to that of the un-encapsulated HAP-MSs. - Abstract: The purpose of this study was to prepare a poly(lactide-co-glycolide) (PLGA) encapsulated hydroxyapatite microspheres (HAP-MSs) as injectable depot for sustained delivery of Doxycycline (Doxy). Doxy loaded HAP-MSs (Doxy-HAP-MSs) were encapsulated with PLGA by solid-in-oil-in-water (S/O/W) emulsion-solvent evaporation technique, the effects of the PLGA used (various intrinsic viscosity and LA/GA ratio) and ratio of PLGA/HAP-MSs on the formation of Doxy-HAP-MSs and in vitro release of Doxy were studied. The results showed that sustained drug release without obvious burst was obtained by using PLGA encapsulated HAP-MSs as the carrier, also the drug release rate could be tailored by changing the ratio of PLGA/HAP-MSs, or PLGA of various intrinsic viscosities or LA/GA ratio. Lower ratio of PLGA/HAP-MSs corresponded faster Doxy release, e.g. for the microspheres of PLGA/HAP-MSs ratio of 8 and 0.25, the in vitro Doxy release percents at the end of 7days were about 23% and 76%, respectively. Higher hydrophilicity (higher ratio of GA to LA) and lower molecular weight of PLGA corresponded to higher Doxy release rates. For in vivo release study, PLGA encapsulated HAP-MSs were subcutaneously injected to the back of mice, and the results showed good correlation between the in vivo and in vitro drug release. Meanwhile, the plasma Doxy levels after subcutaneous administration of PLGA encapsulated Doxy-HAP-MSs were relatively lower and steady

  8. LiFePO4 nanoparticles encapsulated in graphene nanoshells for high-performance lithium-ion battery cathodes.

    Fei, Huilong; Peng, Zhiwei; Yang, Yang; Li, Lei; Raji, Abdul-Rahman O; Samuel, Errol L G; Tour, James M


    LiFePO4 encapsulated in graphene nanoshells (LiFePO4@GNS) nanoparticles were synthesized by solid state reaction between graphene-coated Fe nanoparticles and LiH2PO4. The resulting nanocomposite was demonstrated to be a superior lithium-ion battery cathode with improved cycle and rate performances.

  9. Sol-gel method for encapsulating molecules

    Brinker, C. Jeffrey; Ashley, Carol S.; Bhatia, Rimple; Singh, Anup K.


    A method for encapsulating organic molecules, and in particular, biomolecules using sol-gel chemistry. A silica sol is prepared from an aqueous alkali metal silicate solution, such as a mixture of silicon dioxide and sodium or potassium oxide in water. The pH is adjusted to a suitably low value to stabilize the sol by minimizing the rate of siloxane condensation, thereby allowing storage stability of the sol prior to gelation. The organic molecules, generally in solution, is then added with the organic molecules being encapsulated in the sol matrix. After aging, either a thin film can be prepared or a gel can be formed with the encapsulated molecules. Depending upon the acid used, pH, and other processing conditions, the gelation time can be from one minute up to several days. In the method of the present invention, no alcohols are generated as by-products during the sol-gel and encapsulation steps. The organic molecules can be added at any desired pH value, where the pH value is generally chosen to achieve the desired reactivity of the organic molecules. The method of the present invention thereby presents a sufficiently mild encapsulation method to retain a significant portion of the activity of the biomolecules, compared with the activity of the biomolecules in free solution.

  10. Solution-solid-solid mechanism: superionic conductors catalyze nanowire growth.

    Wang, Junli; Chen, Kangmin; Gong, Ming; Xu, Bin; Yang, Qing


    The catalytic mechanism offers an efficient tool to produce crystalline semiconductor nanowires, in which the choice, state, and structure of catalysts are active research issues of much interest. Here we report a novel solution-solid-solid (SSS) mechanism for nanowire growth catalyzed by solid-phase superionic conductor nanocrystals in low-temperature solution. The preparation of Ag2Se-catalyzed ZnSe nanowires at 100-210 °C is exampled to elucidate the SSS model, which can be extendable to grow other II-VI semiconductor (e.g., CdSe, ZnS, and CdS) nanowires by the catalysis of nanoscale superionic-phase silver or copper(I) chalcogenides (Ag2Se, Ag2S, and Cu2S). The exceptional catalytic ability of these superionic conductors originates from their structure characteristics, known for high-density vacancies and fast mobility of silver or copper(I) cations in the rigid sublattice of Se(2-) or S(2-) ions. Insights into the SSS mechanism are provided based on the formation of solid solution and the solid-state ion diffusion/transport at solid-solid interface between catalyst and nanowire.

  11. Basic properties of semiconductors

    Landsberg, PT


    Since Volume 1 was published in 1982, the centres of interest in the basic physics of semiconductors have shifted. Volume 1 was called Band Theory and Transport Properties in the first edition, but the subject has broadened to such an extent that Basic Properties is now a more suitable title. Seven chapters have been rewritten by the original authors. However, twelve chapters are essentially new, with the bulk of this work being devoted to important current topics which give this volume an almost encyclopaedic form. The first three chapters discuss various aspects of modern band theory and the

  12. Electrowetting on semiconductors

    Palma, Cesar; Deegan, Robert


    Applying a voltage difference between a conductor and a sessile droplet sitting on a thin dielectric film separating it from the conductor will cause the drop to spread. When the conductor is a good metal, the change of the drop's contact angle due to the voltage is given by the Young-Lippmann (YL) equation. Here, we report experiments with lightly doped, single crystal silicon as the conductive electrode. We derive a modified YL equation that includes effects due to the semiconductor and contact line pinning. We show that light induces a non-reversible wetting transition, and that our model agrees well with our experimental results.

  13. Band structure of semiconductors

    Tsidilkovski, I M


    Band Structure of Semiconductors provides a review of the theoretical and experimental methods of investigating band structure and an analysis of the results of the developments in this field. The book presents the problems, methods, and applications in the study of band structure. Topics on the computational methods of band structure; band structures of important semiconducting materials; behavior of an electron in a perturbed periodic field; effective masses and g-factors for the most commonly encountered band structures; and the treatment of cyclotron resonance, Shubnikov-de Haas oscillatio

  14. Semiconductor microcavity polaritons

    Vinogradov, Evgenii A [Institute of Spectroscopy, Russian Academy of Sciences, Troitsk, Moscow region (Russian Federation)


    The optical properties of wide-gap semiconductor films on metal substrates were investigated experimentally by infrared spectroscopy, Raman scattering, and femtosecond spectroscopy techniques as well as theoretically in the framework of linear crystal optics. The optical spectra of such planar structures (microresonators) were shown to bear information on electromagnetic excitations of both the surface and the volume of the structure. The optical spectra are determined by the interaction of all dipole-active excitations of the component materials with the electromagnetic modes of the microresonator, which in turn are determined by the permittivities of each component material, microcavity (microresonator) thickness, and the experimental conditions. (reviews of topical problems)

  15. Physics of Organic Semiconductors

    Brütting, Wolfgang


    Filling the gap in the literature currently available, this book presents an overview of our knowledge of the physics behind organic semiconductor devices. Contributions from 18 international research groups cover various aspects of this field, ranging from the growth of organic layers and crystals, their electronic properties at interfaces, their photophysics and electrical transport properties to the application of these materials in such different devices as organic field-effect transistors, photovoltaic cells and organic light-emitting diodes. From the contents:. * Excitation Dynamics in O

  16. Hydrogen in semiconductors

    Pankove, Jacques I


    Hydrogen plays an important role in silicon technology, having a profound effect on a wide range of properties. Thus, the study of hydrogen in semiconductors has received much attention from an interdisciplinary assortment of researchers. This sixteen-chapter volume provides a comprehensive review of the field, including a discussion of hydrogenation methods, the use of hydrogen to passivate defects, the use of hydrogen to neutralize deep levels, shallow acceptors and shallow donors in silicon, vibrational spectroscopy, and hydrogen-induced defects in silicon. In addition to this detailed cove

  17. Neutron and gamma irradiation effects on power semiconductor switches

    Schwarze, G. E.; Frasca, A. J.


    The performance characteristics of high power semiconductor switches subjected to high levels of neutron fluence and gamma dose must be known by the designer of the power conditioning, control and transmission subsystem of space nuclear power systems. Location and the allowable shielding mass budget will determine the level of radiation tolerance required by the switches to meet performance and reliability requirements. Neutron and gamma ray interactions with semiconductor materials and how these interactions affect the electrical and switching characteristics of solid state power switches is discussed. The experimental measurement system and radiation facilities are described. Experimental data showing the effects of neutron and gamma irradiation on the performance characteristics are given for power-type NPN Bipolar Junction Transistors (BJTs), and Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs). BJTs show a rapid decrease in gain, blocking voltage, and storage time for neutron irradiation, and MOSFETs show a rapid decrease in the gate threshold voltage for gamma irradiation.


    Grant, C D; Zhang, J Z


    This chapter provides an overview of some recent research activities on the study of optical and dynamic properties of semiconductor nanomaterials. The emphasis is on unique aspects of these properties in nanostructures as compared to bulk materials. Linear, including absorption and luminescence, and nonlinear optical as well as dynamic properties of semiconductor nanoparticles are discussed with focus on their dependence on particle size, shape, and surface characteristics. Both doped and undoped semiconductor nanomaterials are highlighted and contrasted to illustrate the use of doping to effectively alter and probe nanomaterial properties. Some emerging applications of optical nanomaterials are discussed towards the end of the chapter, including solar energy conversion, optical sensing of chemicals and biochemicals, solid state lighting, photocatalysis, and photoelectrochemistry.

  19. Semiconductor optoelectronic devices for free-space optical communications

    Katz, J.


    The properties of individual injection lasers are reviewed, and devices of greater complexity are described. These either include or are relevant to monolithic integration configurations of the lasers with their electronic driving circuitry, power combining methods of semiconductor lasers, and electronic methods of steering the radiation patterns of semiconductor lasers and laser arrays. The potential of AlGaAs laser technology for free-space optical communications systems is demonstrated. These solid-state components, which can generate and modulate light, combine the power of a number of sources and perform at least part of the beam pointing functions. Methods are proposed for overcoming the main drawback of semiconductor lasers, that is, their inability to emit the needed amount of optical power in a single-mode operation.

  20. Toward continuous-wave operation of organic semiconductor lasers

    Sandanayaka, Atula S. D.; Matsushima, Toshinori; Bencheikh, Fatima; Yoshida, Kou; Inoue, Munetomo; Fujihara, Takashi; Goushi, Kenichi; Ribierre, Jean-Charles; Adachi, Chihaya


    The demonstration of continuous-wave lasing from organic semiconductor films is highly desirable for practical applications in the areas of spectroscopy, data communication, and sensing, but it still remains a challenging objective. We report low-threshold surface-emitting organic distributed feedback lasers operating in the quasi–continuous-wave regime at 80 MHz as well as under long-pulse photoexcitation of 30 ms. This outstanding performance was achieved using an organic semiconductor thin film with high optical gain, high photoluminescence quantum yield, and no triplet absorption losses at the lasing wavelength combined with a mixed-order distributed feedback grating to achieve a low lasing threshold. A simple encapsulation technique greatly reduced the laser-induced thermal degradation and suppressed the ablation of the gain medium otherwise taking place under intense continuous-wave photoexcitation. Overall, this study provides evidence that the development of a continuous-wave organic semiconductor laser technology is possible via the engineering of the gain medium and the device architecture. PMID:28508042

  1. Nondestructive Assay Options for Spent Fuel Encapsulation

    Tobin, Stephen J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Jansson, Peter [Uppsala Univ. (Sweden)


    This report describes the role that nondestructive assay (NDA) techniques and systems of NDA techniques may have in the context of an encapsulation and deep geological repository. The potential NDA needs of an encapsulation and repository facility include safeguards, heat content, and criticality. Some discussion of the facility needs is given, with the majority of the report concentrating on the capability and characteristics of individual NDA instruments and techniques currently available or under development. Particular emphasis is given to how the NDA techniques can be used to determine the heat production of an assembly, as well as meet the dual safeguards needs of 1) determining the declared parameters of initial enrichment, burn-up, and cooling time and 2) detecting defects (total, partial, and bias). The report concludes with the recommendation of three integrated systems that might meet the combined NDA needs of the encapsulation/repository facility.

  2. Characteristics of DSSC Panels with Silicone Encapsulant

    Jun-Gu Kang


    Full Text Available Dye-sensitized solar cells (DSSC allow light transmission and the application of various colors that make them especially suitable for building-integrated PV (BIPV application. In order to apply DSSC modules to windows, the module has to be panelized: a DSSC module should be protected with toughened glass on the entire surface. Up to the present, it seems to be common to use double glazing with DSSC modules, with air gaps between the glass pane and the DSSC modules. Few studies have been conducted on the characteristics of various glazing methods with DSSC modules. This paper proposes a paneling method that uses silicone encapsulant, analyzing the performance through experimentation. Compared to a multilayered DSSC panel with an air gap, the encapsulant-applied panel showed 6% higher light transmittance and 7% higher electrical efficiency. The encapsulant also prevented electrolyte leakage by strengthening the seals in the DSSC module.

  3. Degradation of Silicone Encapsulants in CPV Optics

    Cai, Can; Miller, David C.; Tappan, Ian A.; Dauskardt, Reinhold H.


    High efficiency multijunction solar cells in terrestrial concentrator photovoltaic (CPV) modules are becoming an increasingly cost effective and viable option in utility scale power generation. As with other utility scale photovoltaics, CPV modules need to guarantee operational lifetimes of at least 25 years. The reliability of optical elements in CPV modules poses a unique materials challenge due to the increased UV irradiance and enhanced temperature cycling associated with concentrated solar flux. The polymeric and thin film materials used in the optical elements are especially susceptible to UV damage, diurnal temperature cycling and active chemical species from the environment. We used fracture mechanics approaches to study the degradation modes including: the adhesion between the encapsulant and the cell or secondary optical element; and the cohesion of the encapsulant itself. Understanding the underlying mechanisms of materials degradation under elevated stress conditions is critical for commercialization of CPV technology and can offer unique insights into degradation modes in similar encapsulants used in other photovoltaic modules.

  4. Suppression of intrinsic roughness in encapsulated graphene

    Thomsen, Joachim Dahl; Gunst, Tue; Gregersen, Søren Schou


    Roughness in graphene is known to contribute to scattering effects which lower carrier mobility. Encapsulating graphene in hexagonal boron nitride (hBN) leads to a significant reduction in roughness and has become the de facto standard method for producing high-quality graphene devices. We have...... fabricated graphene samples encapsulated by hBN that are suspended over apertures in a substrate and used noncontact electron diffraction measurements in a transmission electron microscope to measure the roughness of encapsulated graphene inside such structures. We furthermore compare the roughness...... of these samples to suspended bare graphene and suspended graphene on hBN. The suspended heterostructures display a root mean square (rms) roughness down to 12 pm, considerably less than that previously reported for both suspended graphene and graphene on any substrate and identical within experimental error...

  5. Photogeneration Diffusion and Decay of Charge Carriers in Quantum-Dot Solids

    Gao, Y.


    Semiconductor nanocrystals (NCs), which can have a variety of sizes, shapes and chemical compositions, will be a large and important family of future advanced materials.This thesis focuses on colloidal semiconductor NC solids, also called quantum-dot (QD) solids, which are promising materials for

  6. Semiconductor devices incorporating multilayer interference regions

    Biefeld, Robert M.; Drummond, Timothy J.; Gourley, Paul L.; Zipperian, Thomas E.


    A semiconductor high reflector comprising a number of thin alternating layers of semiconductor materials is electrically tunable and may be used as a temperature insensitive semiconductor laser in a Fabry-Perot configuration.

  7. Effect of cyclodextrins on alpha-chymotrypsin stability and loading in PLGA microspheres upon S/O/W encapsulation.

    Castellanos, Ingrid J; Flores, Giselle; Griebenow, Kai


    The potential of cyclodextrins to stabilize alpha-chymotrypsin upon encapsulation in Poly(lactic-co-glycolic) acid (PLGA) microspheres using a solid-in-oil-in-water (s/o/w) technique was investigated. Two cyclodextrins, hydroxyl-propyl-beta-cyclodextrin (HPbetaCD) and methyl-beta-cyclodextrin (MbetaCD), one insoluble and the other soluble in methylene chloride, were used. The results demonstrate that HPbetaCD failed to stabilize alpha-chymotrypsin upon encapsulation. Specifically, 19% of the protein was aggregated and the specific activity of the enzyme was reduced to ca. 50% of that prior to encapsulation. In contrast, MbetaCD significantly decreased the formation of aggregates to 3% and the retained specific activity of the enzyme was approximately 90%. The co-lyophilization of alpha-chymotrypsin with MbetaCD prior to encapsulation was a requisite to preserve the protein stability in microspheres. Furthermore, MbetaCD prevented the loss of protein during the preparation of microspheres and the encapsulation efficiency was improved to 90%. Release experiments showed the use of MbetaCD modified the release profile: the burst release decreased from 54% (in the absence of the excipient) to 36%. The results suggest that MbetaCD might be a suitable excipient to improve protein stability in s/o/w encapsulation procedures.

  8. Conductors, semiconductors, superconductors. A compact introduction to history, development, and theory of solid-state physics. 2. ed.; Leiter, Halbleiter, Supraleiter. Eine kompakte Einfuehrung in Geschichte, Entwicklung und Theorie der Festkoerperphysik

    Huebener, Rudolf [Tuebingen Univ. (Germany). Fakultaet fuer Mathematik und Physik


    The present book is a strongly revised and supplemented edition of the title: ''Kristalle: Spiefeld der Elektronen'', published scarcely ten years ago by the same author. Especially the physical contents are explained by the mathematically formulated foundations. The book appeals to students of natural sciences and especially of physics as well as to engineers as introduction to the wide field of solid-state physics, so to speak as motivating prestage to the established and very extensive textbooks. Beside the physical contents the book treats the important role of numerous important and often still very young scientists. By corresponding supplements in this book it is tried to present the fundamental developments in their wide environment.

  9. Temperature responsive hydroxypropyl cellulose for encapsulation

    Heitfeld, Kevin A.; Guo, Tingtai; Yang, George; Schaefer, Dale W. (UCIN)


    This work focuses on the use of temperature responsive gels (TRGs) (polymeric hydrogels with a large temperature-dependent change in volume) for flavor retention at cooking temperatures. Specifically, we have studied a gel with a lower critical solution temperature (LCST) that swells at low temperatures and collapses at high temperatures. In the collapsed state, the polymer acts as a transport barrier, keeping the volatile flavors inside. We have successfully synthesized a cellulose gel that exhibits this volume change and have encapsulated an oil phase inside the gel. The flavor-loaded encapsulated oil exhibited an increased release time when compared to similar gelatin capsules.

  10. Performance evaluation soil samples utilizing encapsulation technology

    Dahlgran, James R.


    Performance evaluation soil samples and method of their preparation are described using encapsulation technology to encapsulate analytes which are introduced into a soil matrix for analysis and evaluation by analytical laboratories. Target analytes are mixed in an appropriate solvent at predetermined concentrations. The mixture is emulsified in a solution of polymeric film forming material. The emulsified solution is polymerized to form microcapsules. The microcapsules are recovered, quantitated and introduced into a soil matrix in a predetermined ratio to form soil samples with the desired analyte concentration.

  11. Epoxy Foam Encapsulants: Processing and Dielectric Characterization

    Linda Domeier; Marion Hunter


    The dielectric performance of epoxy foams was investigated to determine if such materials might provide advantages over more standard polyurethane foams in the encapsulation of electronic assemblies. Comparisons of the dielectric characteristics of epoxy and urethane encapsulant foams found no significant differences between the two resin types and no significant difference between as-molded and machined foams. This study specifically evaluated the formulation and processing of epoxy foams using simple methylhydrosiloxanes as the flowing agent and compared the dielectric performance of those to urethane foams of similar density.

  12. Squeezed light in semiconductors

    Ward, M B


    Experimental evidence is presented for the generation of photon-number squeezed states of light as a result of multi-photon absorption. Photon-number squeezing as a result of non-linear absorption has long been predicted and results have been obtained utilising two very different material systems: (i) an AIGaAs waveguide in which high optical intensities can be maintained over a relatively long interaction length of 2 mm; (ii) the organic polymer p-toluene sulphonate polydiacetylene that is essentially a one-dimensional semiconductor possessing a highly nonlinear optical susceptibility. The resulting nonlinear absorption is shown to leave the transmitted light in a state that is clearly nonclassical, exhibiting photon-number fluctuations below the shot-noise limit. Tuning the laser wavelength across the half-bandgap energy has enabled a comparison between two- and three-photon processes in the semiconductor waveguide. The correlations created between different spectral components of a pulsed beam of light as ...

  13. Hydrogen molecules in semiconductors

    Weber, Joerg [Technische Universitaet Dresden, 01062 Dresden (Germany)], E-mail:; Hiller, Martin; Lavrov, Edward V. [Technische Universitaet Dresden, 01062 Dresden (Germany)


    Molecular hydrogen, the simplest of all molecules, allows a direct insight into the fundamental properties of quantum mechanics. In the case of H{sub 2}, the Pauli principle leads to two different species, para-H{sub 2} and ortho-H{sub 2}. A conversion between these species is prohibited. Vibrational mode spectra reflect the fundamental properties and allow an unambiguous identification of the H{sub 2} molecules. Today, we have experimental evidence for the trapping of hydrogen molecules in the semiconductors Si, Ge and GaAs at the interstitial sites, within hydrogen-induced platelets, in voids and at impurities (interstitial oxygen in Si). Interstitial H{sub 2} is a nearly free rotor with a surprisingly simple behavior. We review on interstitial H{sub 2} in semiconductors and report on the unexpected preferential disappearance of the para-H{sub 2} or ortho-D{sub 2} species. The origin of the detected ortho-para conversion will be discussed.

  14. Doped semiconductor nanocrystal junctions

    Borowik, Ł.; Mélin, T., E-mail: [Institut d’Electronique, de Microélectronique et de Nanotechnologie, CNRS-UMR8520, Avenue Poincaré, F-59652 Villeneuve d’Ascq (France); Nguyen-Tran, T.; Roca i Cabarrocas, P. [Laboratoire de Physique des Interfaces et des Couches Minces, CNRS-UMR7647, Ecole Polytechnique, F-91128 Palaiseau (France)


    Semiconductor junctions are the basis of electronic and photovoltaic devices. Here, we investigate junctions formed from highly doped (N{sub D}≈10{sup 20}−10{sup 21}cm{sup −3}) silicon nanocrystals (NCs) in the 2–50 nm size range, using Kelvin probe force microscopy experiments with single charge sensitivity. We show that the charge transfer from doped NCs towards a two-dimensional layer experimentally follows a simple phenomenological law, corresponding to formation of an interface dipole linearly increasing with the NC diameter. This feature leads to analytically predictable junction properties down to quantum size regimes: NC depletion width independent of the NC size and varying as N{sub D}{sup −1/3}, and depleted charge linearly increasing with the NC diameter and varying as N{sub D}{sup 1/3}. We thus establish a “nanocrystal counterpart” of conventional semiconductor planar junctions, here however valid in regimes of strong electrostatic and quantum confinements.

  15. Gating a ferromagnetic semiconductor

    Bove, A.; Altomare, F.; Kundtz, N.; Chang, A. M.; Cho, Y. J.; Liu, X.; Furdyna, J.


    Ferromagnetic semiconductors have the potential of revolutionizing the way current electronic devices work: more so, because they are compatible with current fabrication lines and can easily be integrated with today's technology. Particular interest lies in III-V Diluted Magnetic Semiconductor (DMS), where the ferromagnetism is hole-mediated and the Curie temperature can therefore be tuned by changing the concentration of free carriers. In these systems, most of the effort is currently applied toward the fabrication of devices working at room-temperature: this implies high carrier density accompanied by low mobility and short mean free path. We will report our results for a ferromagnetic 2DHG system with low carrier density (˜3.4E12 cm-2) and mobility (˜ 1000 cm^2/(Vs)), and we will discuss the effects of local gating in light of possible applications to the fabrication of ferromagnetic quantum dots. T. Dietl et al., Phys. Rev. B 63, 195205 (2001). H. Ohno et al., Nature 408, 944 (2000)

  16. Optical coherent control in semiconductors

    Østergaard, John Erland; Vadim, Lyssenko; Hvam, Jørn Märcher


    of quantum control including the recent applications to semiconductors and nanostructures. We study the influence of inhomogeneous broadening in semiconductors on CC results. Photoluminescence (PL) and the coherent emission in four-wave mixing (FWM) is recorded after resonant excitation with phase...

  17. Variable temperature semiconductor film deposition

    Li, Xiaonan; Sheldon, Peter


    A method of depositing a semiconductor material on a substrate. The method sequentially comprises (a) providing the semiconductor material in a depositable state such as a vapor for deposition on the substrate; (b) depositing the semiconductor material on the substrate while heating the substrate to a first temperature sufficient to cause the semiconductor material to form a first film layer having a first grain size; (c) continually depositing the semiconductor material on the substrate while cooling the substrate to a second temperature sufficient to cause the semiconductor material to form a second film layer deposited on the first film layer and having a second grain size smaller than the first grain size; and (d) raising the substrate temperature, while either continuing or not continuing to deposit semiconductor material to form a third film layer, to thereby anneal the film layers into a single layer having favorable efficiency characteristics in photovoltaic applications. A preferred semiconductor material is cadmium telluride deposited on a glass/tin oxide substrate already having thereon a film layer of cadmium sulfide.

  18. II-VI semiconductor compounds


    For condensed matter physicists and electronic engineers, this volume deals with aspects of II-VI semiconductor compounds. Areas covered include devices and applications of II-VI compounds; Co-based II-IV semi-magnetic semiconductors; and electronic structure of strained II-VI superlattices.

  19. Semiconductor photocatalysis principles and applications

    Kisch, Horst


    Focusing on the basic principles of semiconductor photocatalysis, this book also gives a brief introduction to photochemistry, photoelectrochemistry, and homogeneous photocatalysis. In addition, the author - one of the leading authorities in the field - presents important environmental and practical aspects. A valuable, one-stop source for all chemists, material scientists, and physicists working in this area, as well as novice researchers entering semiconductor photocatalysis.

  20. Semiconductor nanostructures in biological applications

    Alexson, Dimitri [Department of Electrical and Computer Engineering, University of Illinois at Chicago, Chicago, IL 60607 (United States); Chen Hongfeng [Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607 (United States); Cho, Michael [Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607 (United States); Department of Physics, University of Illinois at Chicago, Chicago, IL 60607 (United States); Dutta, Mitra [Department of Electrical and Computer Engineering, University of Illinois at Chicago, Chicago, IL 60607 (United States); Department of Physics, University of Illinois at Chicago, Chicago, IL 60607 (United States); Li Yang [Department of Electrical and Computer Engineering, University of Illinois at Chicago, Chicago, IL 60607 (United States); Shi, Peng [Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607 (United States); Raichura, Amit [Department of Electrical and Computer Engineering, University of Illinois at Chicago, Chicago, IL 60607 (United States); Ramadurai, Dinakar [Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607 (United States); Parikh, Shaunak [Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607 (United States); Stroscio, Michael A [Department of Electrical and Computer Engineering, University of Illinois at Chicago, Chicago, IL 60607 (United States); Department of Physics, University of Illinois at Chicago, Chicago, IL 60607 (United States); Vasudev, Milana [Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607 (United States)


    Semiconductor nanostructures in biological applications are discussed. Results are presented on the use of colloidal semiconductor quantum dots both as biological tags and as structures that interact with and influence biomolecules. Results are presented on the use of semiconducting carbon nanotubes in biological applications. (topical review)

  1. Organic semiconductors in a spin

    Samuel, I


    A little palladium can go a long way in polymer-based light-emitting diodes. Inorganic semiconductors such as silicon and gallium arsenide are essential for countless applications in everyday life, ranging from PCs to CD players. However, while they offer unrivalled computational speed, inorganic semiconductors are also rigid and brittle, which means that they are less suited to applications such as displays and flexible electronics. A completely different class of materials - organic semiconductors - are being developed for these applications. Organic semiconductors have many attractive features: they are easy to make, they can emit visible light, and there is tremendous scope for tailoring their properties to specific applications by changing their chemical structure. Research groups and companies around the world have developed a wide range of organic-semiconductor devices, including transistors, light-emitting diodes (LEDs), solar cells and lasers. (U.K.)

  2. Semiconductors for Plasmonics and Metamaterials

    Naik, Gururaj V; 10.1002/pssr.201004269


    Plasmonics has conventionally been in the realm of metal-optics. However, conventional metals as plasmonic elements in the near-infrared (NIR) and visible spectral ranges suffer from problems such as large losses and incompatibility with semiconductor technology. Replacing metals with semiconductors can alleviate these problems if only semiconductors could exhibit negative real permittivity. Aluminum doped zinc oxide (AZO) is a low loss semiconductor that can show negative real permittivity in the NIR. A comparative assessment of AZO-based plasmonic devices such as superlens and hyperlens with their metal-based counterparts shows that AZO-based devices significantly outperform at a wavelength of 1.55 um. This provides a strong stimulus in turning to semiconductor plasmonics at the telecommunication wavelengths.

  3. Applied solid state science advances in materials and device research

    Wolfe, Raymond


    Applied Solid State Science: Advances in Materials and Device Research, Volume 1 presents articles about junction electroluminescence; metal-insulator-semiconductor (MIS) physics; ion implantation in semiconductors; and electron transport through insulating thin films. The book describes the basic physics of carrier injection; energy transfer and recombination mechanisms; state of the art efficiencies; and future prospects for light emitting diodes. The text then discusses solid state spectroscopy, which is the pair spectra observed in gallium phosphide photoluminescence. The extensive studies

  4. Encapsulation into complex coacervate core micelles promotes EGFP dimerization

    Nolles, A.; Dongen, Van N.J.E.; Westphal, A.H.; Visser, A.J.W.G.; Kleijn, J.M.; Berkel, Van W.J.H.; Borst, J.W.


    Complex coacervate core micelles (C3Ms) are colloidal structures useful for encapsulation of biomacromolecules. We previously demonstrated that enhanced green fluorescent protein (EGFP) can be encapsulated into C3Ms using the diblock copolymer

  5. Prediction and theoretical characterization of p-type organic semiconductor crystals for field-effect transistor applications.

    Atahan-Evrenk, Sule; Aspuru-Guzik, Alán


    The theoretical prediction and characterization of the solid-state structure of organic semiconductors has tremendous potential for the discovery of new high performance materials. To date, the theoretical analysis mostly relied on the availability of crystal structures obtained through X-ray diffraction. However, the theoretical prediction of the crystal structures of organic semiconductor molecules remains a challenge. This review highlights some of the recent advances in the determination of structure-property relationships of the known organic semiconductor single-crystals and summarizes a few available studies on the prediction of the crystal structures of p-type organic semiconductors for transistor applications.

  6. Solvent vapor annealing of an insoluble molecular semiconductor

    Amassian, Aram


    Solvent vapor annealing has been proposed as a low-cost, highly versatile, and room-temperature alternative to thermal annealing of organic semiconductors and devices. In this article, we investigate the solvent vapor annealing process of a model insoluble molecular semiconductor thin film - pentacene on SiO 2 exposed to acetone vapor - using a combination of optical reflectance and two-dimensional grazing incidence X-ray diffraction measurements performed in situ, during processing. These measurements provide valuable and new insight into the solvent vapor annealing process; they demonstrate that solvent molecules interact mainly with the surface of the film to induce a solid-solid transition without noticeable swelling, dissolving or melting of the molecular material. © 2010 The Royal Society of Chemistry.

  7. Encapsulation of thermal energy storage media

    Dhau, Jaspreet; Goswami, Dharendra; Jotshi, Chand K.; Stefanakos, Elias K.


    In one embodiment, a phase change material is encapsulated by forming a phase change material pellet, coating the pellet with flexible material, heating the coated pellet to melt the phase change material, wherein the phase change materials expands and air within the pellet diffuses out through the flexible material, and cooling the coated pellet to solidify the phase change material.

  8. Secure Hybrid Encryption from Weakened Key Encapsulation

    D. Hofheinz (Dennis); E. Kiltz (Eike); A. Menezes


    textabstractWe put forward a new paradigm for building hybrid encryption schemes from constrained chosen-ciphertext secure (CCCA) key-encapsulation mechanisms (KEMs) plus authenticated symmetric encryption. Constrained chosen-ciphertext security is a new security notion for KEMs that we propose. It

  9. Antidiabetic Activity from Gallic Acid Encapsulated Nanochitosan

    Purbowatiningrum; Ngadiwiyana; Ismiyarto; Fachriyah, E.; Eviana, I.; Eldiana, O.; Amaliyah, N.; Sektianingrum, A. N.


    Diabetes mellitus (DM) has become a health problem in the world because it causes death. One of the phenolic compounds that have antidiabetic activity is gallic acid. However, the use of this compound still provides unsatisfactory results due to its degradation during the absorption process. The solution offered to solve the problem is by encapsulated it within chitosan nanoparticles that serve to protect the bioactive compound from degradation, increases of solubility and delivery of a bioactive compound to the target site by using freeze-drying technique. The result of chitosan nanoparticle’s Scanning Electron Microscopy (SEM) showed that chitosan nanoparticle’s size is uniform and it is smaller than chitosan. The value of encapsulation efficiency (EE) of gallic acid which encapsulated within chitosan nanoparticles is about 50.76%. Inhibition test result showed that gallic acid-chitosan nanoparticles at 50 ppm could inhibite α-glucosidase activity in 28.87% with 54.94 in IC50. So it can be concluded that gallic acid can be encapsulated in nanoparticles of chitosan and proved that it could inhibit α-glucosidase.

  10. Treatment of Diabetes with Encapsulated Islets

    de Vos, Paul; Spasojevic, Milica; Faas, Marijke M.; Pedraz, JL; Orive, G


    Cell encapsulation has been proposed for the treatment of a wide variety of diseases since it allows for transplantation of cells in the absence of undesired immunosuppression. The technology has been proposed to be a solution for the treatment of diabetes since it potentially allows a mandatory

  11. Liposome-Encapsulated Hemoglobin for Emergency Resuscitation.


    have infused liposome -encapsulated amphotericin B to treat patients with systemic fungal infections. Their formulation includes 30% dimyristoyl...procedure, including exploring new industrial-scale methodologies for liposome manufacture. In addition we have focused on basic problems of biophysics...circulation persistance of this new formulation , as produced by the Microfluidizer, is obviously necessary. The influence of negatively-charged lipids on

  12. An Investigation of Membrane-Encapsulated Trypanocides.


    M) SUV by soybean phosphtolipids MLV was negligible. This suggests that the encapsulation of a preformed * SUV by MIV may be related to the...lipid/g tissue was comparable to that of the same liposomes subjected to centrifugation at 10,000 g for 3 min (13) at an injected dose of 99 vig lipld/g

  13. Treatment of Diabetes with Encapsulated Islets

    de Vos, Paul; Spasojevic, Milica; Faas, Marijke M.; Pedraz, JL; Orive, G


    Cell encapsulation has been proposed for the treatment of a wide variety of diseases since it allows for transplantation of cells in the absence of undesired immunosuppression. The technology has been proposed to be a solution for the treatment of diabetes since it potentially allows a mandatory min

  14. Synthesis and catalytic properties of metal clusters encapsulated within small-pore (SOD, GIS, ANA) zeolites.

    Goel, Sarika; Wu, Zhijie; Zones, Stacey I; Iglesia, Enrique


    The synthesis protocols for encapsulation of metal clusters reported here expand the diversity in catalytic chemistries made possible by the ability of microporous solids to select reactants, transition states, and products on the basis of their molecular size. We report a synthesis strategy for the encapsulation of noble metals and their oxides within SOD (Sodalite, 0.28 nm × 0.28 nm), GIS (Gismondine, 0.45 nm × 0.31 nm), and ANA (Analcime, 0.42 nm × 0.16 nm) zeolites. Encapsulation was achieved via direct hydrothermal synthesis for SOD and GIS using metal precursors stabilized by ammonia or organic amine ligands, which prevent their decomposition or precipitation as colloidal hydroxides at the conditions of hydrothermal synthesis (12), thereby causing precipitation of even ligand-stabilized metal precursors as hydroxides. As a result, encapsulation was achieved by the recrystallization of metal clusters containing GIS into ANA, which retained these metal clusters within voids throughout the GIS-ANA transformation.

  15. The inhibitory effect of disulfiram encapsulated PLGA NPs on tumor growth: Different administration routes.

    Fasehee, Hamidreza; Zarrinrad, Ghazaleh; Tavangar, Seyed Mohammad; Ghaffari, Seyed Hamidollah; Faghihi, Shahab


    The strong anticancer activity of disulfiram is hindered by its rapid degradation in blood system. A novel folate-receptor-targeted poly (lactide-co-glycolide) (PLGA)-polyethylene glycol (PEG) nanoparticle (NP) is developed for encapsulation and delivery of disulfiram into breast cancer tumor using passive (EPR effect) and active (folate receptor) targeting. The anticancer activity of disulfiram and its effect on caspase-3 activity and cell cycle are studied. The administration of encapsulated PLGA NPs using intra-peritoneal, intravenous and intra-tumor routes is investigated using animal model. Disulfiram shows strong cytotoxicity against MCF7 cell line. The activity of caspase-3 inhibited with disulfiram via dose dependent manner while the drug causes cell cycle arrest in G0/G1 and S phase time-dependently. The encapsulated disulfiram shows higher activity in apoptosis induction as compared to free drug. In nontoxic dose of encapsulated disulfiram, the highest and lowest efficacy of NPs in tumor growth inhibition is observed for intravenous injection and intraperitoneal injection. It is suggested that administration of disulfiram by targeted PLGA nanoparticles using intravenous injection would present an alternative therapeutic approach for solid tumor treatment.

  16. Evaluation of Different Analysis Methods for the Encapsulation Efficiency of Amylose Inclusion Compound

    Tao Feng


    Full Text Available Recently amylose has drawn much attention as a potential vehicle for the nanoencapsulation of different flavor molecules, and the encapsulation efficiency of the complex is an important index for the evaluation of its embedding effect. In this study, three different methods for assessing encapsulation efficiency of amylose-flavor complexes were compared. We chose heptanol and menthone as the flavor molecules, as both of them exhibit a typical odor. The complexes were prepared by the melting method, and their structures were characterized by XRD. In addition, the encapsulation efficiency was determined by thermal gravimetric analysis (TGA, potentiometric titration (PT, and headspace solid phase microextraction gas chromatography (HS-SPME-GC, respectively. The results showed that PT results were within the reported literature range while HS-SPME-GC seemed to overestimate the results and TGA results were the lowest. What is more, the operations of TGA and PT were relatively simple and the results were reproducible, while the HS-SPME-GC method displayed excellent high sensitivity. Therefore, PT method is the best method for assessing encapsulation efficiency of amylose-flavor complexes.

  17. Laser Cooling of Solids


    observed in a range of glasses and crystals doped with Yb3+ (ZBLANP [19–22], ZBLAN [23,24], CNBZn [9,25] BIG [25, 26], KGd(WO4)2 [9], KY(WO4)2 [9], YAG [27...Yb3+-doped fluorozirconate glass ZBLAN , Phys. Rev. B 75, 144302 (2007). [40] C. W. Hoyt, Laser Cooling in Thulium-doped Solids, Ph. D., optical refrigeration research has been confined to glasses and crystals doped with rare- earth elements and direct-band semiconductors such as

  18. Semiconductor nanowire lasers

    Eaton, Samuel W.; Fu, Anthony; Wong, Andrew B.; Ning, Cun-Zheng; Yang, Peidong


    The discovery and continued development of the laser has revolutionized both science and industry. The advent of miniaturized, semiconductor lasers has made this technology an integral part of everyday life. Exciting research continues with a new focus on nanowire lasers because of their great potential in the field of optoelectronics. In this Review, we explore the latest advancements in the development of nanowire lasers and offer our perspective on future improvements and trends. We discuss fundamental material considerations and the latest, most effective materials for nanowire lasers. A discussion of novel cavity designs and amplification methods is followed by some of the latest work on surface plasmon polariton nanowire lasers. Finally, exciting new reports of electrically pumped nanowire lasers with the potential for integrated optoelectronic applications are described.

  19. Semiconductor adiabatic qubits

    Carroll, Malcolm S.; Witzel, Wayne; Jacobson, Noah Tobias; Ganti, Anand; Landahl, Andrew J.; Lilly, Michael; Nguyen, Khoi Thi; Bishop, Nathaniel; Carr, Stephen M.; Bussmann, Ezra; Nielsen, Erik; Levy, James Ewers; Blume-Kohout, Robin J.; Rahman, Rajib


    A quantum computing device that includes a plurality of semiconductor adiabatic qubits is described herein. The qubits are programmed with local biases and coupling terms between qubits that represent a problem of interest. The qubits are initialized by way of a tuneable parameter, a local tunnel coupling within each qubit, such that the qubits remain in a ground energy state, and that initial state is represented by the qubits being in a superposition of |0> and |1> states. The parameter is altered over time adiabatically or such that relaxation mechanisms maintain a large fraction of ground state occupation through decreasing the tunnel coupling barrier within each qubit with the appropriate schedule. The final state when tunnel coupling is effectively zero represents the solution state to the problem represented in the |0> and |1> basis, which can be accurately read at each qubit location.

  20. A semiconductor based electrode

    Khamatani, A.; Kobayasi, K.


    The semiconductor electrode is submerged into an electrolyte which is held in the illuminated chamber. The other electrode is placed in a dark chamber connected with the channel to be illuminated, which has a partition in the form of a membrane. An electric current flows in the external circuit of the element with illumination of the first electrode. The illuminated electrode is covered with a thin film of a substance which is stable with the action of the electrolyte. The film is made of Si02, A1203, GaN or A1N. The protective coating makes it possible to use materials less stable than Ti02 in a rutile modification, but which have higher characteristics than the GaP, GaAs, CdS and InP, for making the electrode.

  1. Mechanical Robustness and Hermeticity Monitoring for MEMS Thin Film Encapsulation

    Santagata, F.


    Many Micro-Electro-Mechanical-Systems (MEMS) require encapsulation, to prevent delicate sensor structures being exposed to external perturbations such as dust, humidity, touching, and gas pressure. An upcoming and cost-effective way of encapsulation is zero-level packaging or thin-film encapsulation

  2. Spectroscopic characterisation of the erbium impurity in crystalline semiconductors

    Ammerlaan, C. A. J.


    A scheme for the numerical calculation of energy levels of rare-earth ions in a crystalline solid is presented. Stark fields of cubic, trigonal, tetragonal, orthorhombic and monoclinic symmetry are considered. As examples, optical luminescence spectra of erbium in the semiconductors zinc selenide and silicon are analysed. Based on the optical characterisation, the g tensors for Zeeman splitting in an applied magnetic field are predicted for the crystal-field ground states of these centres.

  3. Effects of external stress on defect complexes in semiconductors

    Tessema, Genene [Department of Physics, Addis Ababa University, PO Box 1176, Addis Ababa (Ethiopia); Helmholtz-Institut fuer Strahlen und Kernphysik, Nussalle 14-16, 53115 Bonn (Germany)


    Crystal field gradients that exist at lattice sites in solids depend on the symmetry of charge distribution around atomic sites. The charge symmetry could be broken either by the presence of impurity complexes in the host matrix or by external stress on the samples, which leads to an observable magnitude of electric field gradients (EFGs). The perturbed {gamma}-{gamma} angular correlation (PAC) method is employed here to investigate the effect of uniaxial stress on {sup 111}Cd sites in crystalline doped semiconductors.

  4. Nondestructive Encapsulation of CdSe/CdS Quantum Dots in an Inorganic Matrix by Pulsed Laser Deposition.

    Aubret, Antoine; Houel, Julien; Pereira, Antonio; Baronnier, Justine; Lhuillier, Emmanuel; Dubertret, Benoit; Dujardin, Christophe; Kulzer, Florian; Pillonnet, Anne


    We report the successful encapsulation of colloidal quantum dots in an inorganic matrix by pulsed laser deposition. Our technique is nondestructive and thus permits the incorporation of CdSe/CdS core/shell colloidal quantum dots in an amorphous yttrium oxide matrix (Y2O3) under full preservation of the advantageous optical properties of the nanocrystals. We find that controlling the kinetic energy of the matrix precursors by means of the oxygen pressure in the deposition chamber facilitates the survival of the encapsulated species, whose well-conserved optical properties such as emission intensity, luminescence spectrum, fluorescence lifetime, and efficiency as single-photon emitters we document in detail. Our method can be extended to different types of nanoemitters (e.g., nanorods, dots-in-rods, nanoplatelets) as well as to other matrices (oxides, semiconductors, metals), opening up new vistas for the realization of fully inorganic multilayered active devices based on colloidal nano-objects.

  5. Cryopreservation of Dendrobium heterocarpum Lindl. via encapsulation-dehydration method

    Witaya Pimda


    Full Text Available The species Dendrobium heterocarpum Lindl., a wild orchid native to north and northeastThailand, creates an aura of mystique and grandeur with their intricate flower appearance which enthralsmany collectors within the country. An increase in collection for trade or any orther purposes may lead toa dramatic decrase in the population of this species, thus becoming rare or endangered species in thenear future. Cryopreservation is an alternative means for conservation of plant genetic resourceswhich can be applied to this species. This study, therefore, was aimed to optimize the conditions forencapsulation-dehydration method in D. heterocarpum. The protocorms were successfully cryopreservedas the following protocol. The protocorms were encapsulated with Ca-alginate, precultured on solid NDmedium supplemented with 0.25 M sucrose for 1 week in the dark at 0°C and subsequently preculturedin liquid ND medium supplemented with 0.25 M sucrose for 2 days in the dark at 0°C. Then, they weredehydrated by air-drying for 12 hours and plunged into LN for 1 day. Recovery percentage was 8.33%after 2 weeks of regrowth. However, preculture with ABA was found to insufficiently enhance freezingand thawing tolerance. TTC staining was negative and further regrowth on solid ND medium confirmedno survival of the cryopreserved protocorms.

  6. Accurate ionization potential of semiconductors from efficient density functional calculations

    Ye, Lin-Hui


    Despite its huge successes in total-energy-related applications, the Kohn-Sham scheme of density functional theory cannot get reliable single-particle excitation energies for solids. In particular, it has not been able to calculate the ionization potential (IP), one of the most important material parameters, for semiconductors. We illustrate that an approximate exact-exchange optimized effective potential (EXX-OEP), the Becke-Johnson exchange, can be used to largely solve this long-standing problem. For a group of 17 semiconductors, we have obtained the IPs to an accuracy similar to that of the much more sophisticated G W approximation (GWA), with the computational cost of only local-density approximation/generalized gradient approximation. The EXX-OEP, therefore, is likely as useful for solids as for finite systems. For solid surfaces, the asymptotic behavior of the vx c has effects similar to those of finite systems which, when neglected, typically cause the semiconductor IPs to be underestimated. This may partially explain why standard GWA systematically underestimates the IPs and why using the same GWA procedures has not been able to get an accurate IP and band gap at the same time.

  7. Semiconductor Nanocrystals for Biological Imaging

    Fu, Aihua; Gu, Weiwei; Larabell, Carolyn; Alivisatos, A. Paul


    Conventional organic fluorophores suffer from poor photo stability, narrow absorption spectra and broad emission feature. Semiconductor nanocrystals, on the other hand, are highly photo-stable with broad absorption spectra and narrow size-tunable emission spectra. Recent advances in the synthesis of these materials have resulted in bright, sensitive, extremely photo-stable and biocompatible semiconductor fluorophores. Commercial availability facilitates their application in a variety of unprecedented biological experiments, including multiplexed cellular imaging, long-term in vitro and in vivo labeling, deep tissue structure mapping and single particle investigation of dynamic cellular processes. Semiconductor nanocrystals are one of the first examples of nanotechnology enabling a new class of biomedical applications.

  8. Semiconductor Eutectic Solar Cell.


    plastic plate with one of the following materials: paraffin, stearic acid, beeswax or phenyl salicylate. It was found that phenyl salicylate is the most...44b. During alloying, the melt tin film dissolved a small amount of SnSe according to a solid solubility curve at the alloying temperature. And since

  9. High Performance Organic Semiconductors


    a stable, solid-state source of fluoride ions that activate the silane ; (2) a Sonogashira-type condensation with dTDPP. This synthetic largely red-shifted, absorbing primarily between 550 nm and 900 nm. From their molecular weights, it can be calculated that the batches of Ph

  10. Semiconductor device PN junction fabrication using optical processing of amorphous semiconductor material

    Sopori, Bhushan; Rangappan, Anikara


    Systems and methods for semiconductor device PN junction fabrication are provided. In one embodiment, a method for fabricating an electrical device having a P-N junction comprises: depositing a layer of amorphous semiconductor material onto a crystalline semiconductor base, wherein the crystalline semiconductor base comprises a crystalline phase of a same semiconductor as the amorphous layer; and growing the layer of amorphous semiconductor material into a layer of crystalline semiconductor material that is epitaxially matched to the lattice structure of the crystalline semiconductor base by applying an optical energy that penetrates at least the amorphous semiconductor material.

  11. Solid-state dynamics of uranyl polyoxometalates.

    Alam, Todd M; Liao, Zuolei; Zakharov, Lev N; Nyman, May


    Understanding fundamental uranyl polyoxometalate (POM) chemistry in solution and the solid state is the first step to defining its future role in the development of new actinide materials and separation processes that are vital to every step of the nuclear fuel cycle. Many solid-state geometries of uranyl POMs have been described, but we are only beginning to understand their chemical behavior, which thus far includes the role of templates in their self-assembly, and the dynamics of encapsulated species in solution. This study provides unprecedented detail into the exchange dynamics of the encapsulated species in the solid state through Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR) spectroscopy. Although it was previously recognized that capsule-like molybdate and uranyl POMs exchange encapsulated species when dissolved in water, analogous exchange in the solid state has not been documented, or even considered. Here, we observe the extremely high rate of transport of Li(+) and aqua species across the uranyl shell in the solid state, a process that is affected by both temperature and pore blocking by larger species. These results highlight the untapped potential of emergent f-block element materials and vesicle-like POMs. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Acoustically excited encapsulated microbubbles and mitigation of biofouling

    Qamar, Adnan


    Provided herein is a universally applicable biofouling mitigation technology using acoustically excited encapsulated microbubbles that disrupt biofilm or biofilm formation. For example, a method of reducing biofilm formation or removing biofilm in a membrane filtration system is provided in which a feed solution comprising encapsulated microbubbles is provided to the membrane under conditions that allow the encapsulated microbubbles to embed in a biofilm. Sonication of the embedded, encapsulated microbubbles disrupts the biofilm. Thus, provided herein is a membrane filtration system for performing the methods and encapsulated microbubbles specifically selected for binding to extracellular polymeric substances (EFS) in a biofilm.

  13. Solid State Laser


    The Titan-CW Ti:sapphire (titanium-doped sapphire) tunable laser is an innovation in solid-state laser technology jointly developed by the Research and Solid State Laser Divisions of Schwartz Electro-optics, Inc. (SEO). SEO is producing the laser for the commercial market, an outgrowth of a program sponsored by Langley Research Center to develop Ti:sapphire technology for space use. SEO's Titan-CW series of Ti:sapphire tunable lasers have applicability in analytical equipment designed for qualitative analysis of carbohydrates and proteins, structural analysis of water, starch/sugar analyses, and measurements of salt in meat. Further applications are expected in semiconductor manufacture, in medicine for diagnosis and therapy, and in biochemistry.

  14. Solar Water Splitting Using Semiconductor Photocatalyst Powders

    Takanabe, Kazuhiro


    Solar energy conversion is essential to address the gap between energy production and increasing demand. Large scale energy generation from solar energy can only be achieved through equally large scale collection of the solar spectrum. Overall water splitting using heterogeneous photocatalysts with a single semiconductor enables the direct generation of H from photoreactors and is one of the most economical technologies for large-scale production of solar fuels. Efficient photocatalyst materials are essential to make this process feasible for future technologies. To achieve efficient photocatalysis for overall water splitting, all of the parameters involved at different time scales should be improved because the overall efficiency is obtained by the multiplication of all these fundamental efficiencies. Accumulation of knowledge ranging from solid-state physics to electrochemistry and a multidisciplinary approach to conduct various measurements are inevitable to be able to understand photocatalysis fully and to improve its efficiency.

  15. TiO/sub 2/ and CdS colloids stabilized by. beta. -cyclodextrins: tailored semiconductor-receptor systems as a means to control interfacial electron-transfer processes

    Willner, I.; Eichen, Y.


    The photocatalytic activity of semiconductor particles is of substantial interest in synthesis as well as a means of solar energy conversion and storage. Electron-transfer reactions such as charge ejection or charge injection at semiconductor - solution interfaces are important factors that control the photocatalytic activity of the semiconductors. Electrostatic attraction of solute to the semiconductor surface has improved charge ejection from the excited semiconductor to solute relays. Adsorption of dyes to the semiconductor surface, i.e., by hydrophobic interactions, resulted in effective charge injection to the semiconductor and consequently the photocatalytic activity of semiconductors operative in the UV region could be shifted to the visible absorption spectrum. Substantial efforts have also been directed in recent years toward the preparation of semiconductor particles in colloidal forms to improve their light harvesting and interfacial electron-transfer properties. Stabilization of semiconductor colloids by polymers, microemulsions, and vesicle encapsulation has been reported. Here they report on a novel method for stabilizing semiconductor colloids by ..beta..-cyclodextrin (..beta..-CD).

  16. Atomic layer deposition for semiconductors

    Hwang, Cheol Seong


    This edited volume discusses atomic layer deposition (ALD) for all modern semiconductor devices, moving from the basic chemistry of ALD and modeling of ALD processes to sections on ALD for memories, logic devices, and machines.

  17. Metal-Insulator-Semiconductor Photodetectors

    Chu-Hsuan Lin


    Full Text Available The major radiation of the Sun can be roughly divided into three regions: ultraviolet, visible, and infrared light. Detection in these three regions is important to human beings. The metal-insulator-semiconductor photodetector, with a simpler process than the pn-junction photodetector and a lower dark current than the MSM photodetector, has been developed for light detection in these three regions. Ideal UV photodetectors with high UV-to-visible rejection ratio could be demonstrated with III-V metal-insulator-semiconductor UV photodetectors. The visible-light detection and near-infrared optical communications have been implemented with Si and Ge metal-insulator-semiconductor photodetectors. For mid- and long-wavelength infrared detection, metal-insulator-semiconductor SiGe/Si quantum dot infrared photodetectors have been developed, and the detection spectrum covers atmospheric transmission windows.

  18. Metal-insulator-semiconductor photodetectors.

    Lin, Chu-Hsuan; Liu, Chee Wee


    The major radiation of the sun can be roughly divided into three regions: ultraviolet, visible, and infrared light. Detection in these three regions is important to human beings. The metal-insulator-semiconductor photodetector, with a simpler process than the pn-junction photodetector and a lower dark current than the MSM photodetector, has been developed for light detection in these three regions. Ideal UV photodetectors with high UV-to-visible rejection ratio could be demonstrated with III-V metal-insulator-semiconductor UV photodetectors. The visible-light detection and near-infrared optical communications have been implemented with Si and Ge metal-insulator-semiconductor photodetectors. For mid- and long-wavelength infrared detection, metal-insulator-semiconductor SiGe/Si quantum dot infrared photodetectors have been developed, and the detection spectrum covers atmospheric transmission windows.

  19. Semiconductor nanoparticles for quantum devices

    Erokhin, Victor; Carrara, Sandro; Amenitch, H.; Bernstorff, S.; Nicolini, Claudio


    Semiconductor nanoparticles were synthesized by exposing fatty acid salt Langmuir-Blodgett films to the atmosphere of 0957-4484/9/3/004/img8. The particle sizes were characterized by small-angle x-ray scattering of their solutions using synchrotron radiation source at higher resolution, as it was impossible previously to study it with usual laboratory x-ray sources. The particle sizes were found to correspond with the demands of single-electron and quantum junctions. Semiconductor heterostructures were grown by self-aggregation of these particles of different types. Electrical properties of these nanostructures were studied by using STM. Voltage-current characteristics revealed the presence of differential negative resistance. Measurements confirmed the formation of semiconductor superlattices directed towards a development of new nanodevices, such as tunnelling diodes and semiconductor lasers.

  20. Quantum optics with semiconductor nanostructures

    Jahnke, Frank


    A guide to the theory, application and potential of semiconductor nanostructures in the exploration of quantum optics. It offers an overview of resonance fluorescence emission.$bAn understanding of the interaction between light and matter on a quantum level is of fundamental interest and has many applications in optical technologies. The quantum nature of the interaction has recently attracted great attention for applications of semiconductor nanostructures in quantum information processing. Quantum optics with semiconductor nanostructures is a key guide to the theory, experimental realisation, and future potential of semiconductor nanostructures in the exploration of quantum optics. Part one provides a comprehensive overview of single quantum dot systems, beginning with a look at resonance fluorescence emission. Quantum optics with single quantum dots in photonic crystal and micro cavities are explored in detail, before part two goes on to review nanolasers with quantum dot emitters. Light-matter interaction...

  1. Thin film Encapsulations of Flexible Organic Light Emitting Diodes

    Tsai Fa-Ta


    Full Text Available Various encapsulated films for flexible organic light emitting diodes (OLEDs were studied in this work, where gas barrier layers including inorganic Al2O3 thin films prepared by atomic layer deposition, organic Parylene C thin films prepared by chemical vapor deposition, and their combination were considered. The transmittance and water vapor transmission rate of the various organic and inorgabic encapsulated films were tested. The effects of the encapsulated films on the luminance and current density of the OLEDs were discussed, and the life time experiments of the OLEDs with these encapsulated films were also conducted. The results showed that the transmittance are acceptable even the PET substrate were coated two Al2O3 and Parylene C layers. The results also indicated the WVTR of the PET substrate improved by coating the barrier layers. In the encapsulation performance, it indicates the OLED with Al2O3 /PET, 1 pair/PET, and 2 pairs/PET presents similarly higher luminance than the other two cases. Although the 1 pair/PET encapsulation behaves a litter better luminance than the 2 pairs/PET encapsulation, the 2 pairs/PET encapsulation has much better life time. The OLED with 2 pairs/PET encapsulation behaves near double life time to the 1 pair encapsulation, and four times to none encapsulation.

  2. Solid-State Nuclear Power

    George, Jeffrey A.


    A strategy for "Solid-State" Nuclear Power is proposed to guide development of technologies and systems into the second 50 years of nuclear spaceflight. The strategy emphasizes a simple and highly integrated system architecture with few moving parts or fluid loops; the leverage of modern advances in materials, manufacturing, semiconductors, microelectromechanical and nanotechnology devices; and the targeted advancement of high temperature nuclear fuels, materials and static power conversion to enable high performance from simple system topologies.

  3. Stabilization and encapsulation of photosensitive resveratrol within yeast cell.

    Shi, Guorong; Rao, Liqun; Yu, Huazhong; Xiang, Hua; Yang, Hua; Ji, Runa


    The photosensitive resveratrol was successfully encapsulated in yeast cells for the first time, as characterized by FT-IR spectra, fluorescence and confocal micrographs of the yeast cells, resveratrol and microcapsules. The release characteristic of the obtained yeast-encapsulated resveratrol in simulated gastric fluid was evaluated, and its storage stability as a powder was investigated at 25 degrees C/75% relative humidity (RH), 25 degrees C/90% RH and 60 degrees C under the laboratory fluorescent lighting conditions (ca. 300 lx) or in the dark. Also, the scavenging capacity of yeast-encapsulated resveratrol on DPPH radical was compared with that of non-encapsulated resveratrol. It could be demonstrated clearly that no chemical changes occurred during the encapsulation. Besides, the DPPH radical-scavenging activity increased after the encapsulation. In addition, the yeast-encapsulated resveratrol exhibited good stability, and its bioavailability was enhanced as a result of increased solubility of resveratrol and sustained releasing.

  4. 銳鈦型TiO2性能研究 II.銳鈦型TiO2的光化學活性封閉及表徵%Studies on the Properties of Anatase TiO2 II.The Encapsulation and Characterization of Photochemical Activity of Anatase TiO2

    高丕英; 溫占秀; 方圖南; 於遵巨集; 古巨集晨


      In this paper,the hydrothermal surface modification with silica was applied to encapsulate the surface photochemiacl activity of anatase TiO2. The reducing reaction of Cr2O72- was used to evaluate the integraty of the encapsulation layer. Some factors,e.g., TiO2 slurry solid concentration,temperature and pH,as well as reaction time which dominate the encapsulation, were studied too.

  5. Semiconductor packaging materials interaction and reliability

    Chen, Andrea


    In semiconductor manufacturing, understanding how various materials behave and interact is critical to making a reliable and robust semiconductor package. Semiconductor Packaging: Materials Interaction and Reliability provides a fundamental understanding of the underlying physical properties of the materials used in a semiconductor package. The book focuses on an important step in semiconductor manufacturing--package assembly and testing. It covers the basics of material properties and explains how to determine which behaviors are important to package performance. The authors also discuss how

  6. Optical Orientation in Ferromagnet/Semiconductor Hybrids

    Korenev, V. L.


    The physics of optical pumping of semiconductor electrons in the ferromagnet/semiconductor hybrids is discussed. Optically oriented semiconductor electrons detect the magnetic state of the ferromagnetic film. In turn, the ferromagnetism of the hybrid can be controlled optically with the help of the semiconductor. Spin-spin interactions near the interface ferromagnet/semiconductor play crucial role in the optical readout and the manipulation of ferromagnetism.

  7. Seebeck effect in polycrystalline semiconductors

    Jerhot, J.; Vlcek, J.


    The paper deals with the interpretation of the Seebeck coefficient measured for a polycrystalline semiconductor. Polycrystalline semiconductors are considered to be composed of grains separated from one another by intergrain domains. An isotype heterojunction with a certain density of interface states is assumed to exist at the grain-intergrain domain interface. The general formula for the Seebeck coefficient under these conditions is derived. The relations valid for systems of practical interest are shown as limiting cases of the formula presented.

  8. Fractal properties of nanostructured semiconductors

    Zhanabaev, Z.Zh. [Al-Farabi Khazakh National University, Tole bi Street, 96, Almaty 050012 (Kazakhstan); Grevtseva, T.Yu. [Al-Farabi Khazakh National University, Tole bi Street, 96, Almaty 050012 (Kazakhstan)]. E-mail:


    A theory for the temperature and time dependence of current carrier concentration in semiconductors with different non-equilibrium nanocluster structure has been developed. It was shown that the scale-invariant fractal self-similar and self-affine laws can exist near by the transition point to the equilibrium state. Results of the theory have been compared to the experimental data from electrical properties of semiconductor films with nanoclusters.

  9. A semiconductor laser excitation circuit

    Kaadzunari, O.; Masaty, K.


    A semiconductor laser excitation circuit is patented that is designed for operation in a pulsed mode with a high pulse repetition frequency. This circuit includes, in addition to a semiconductor laser, a high speed photodetector, a reference voltage source, a comparator, and a pulse oscillator and modulator. If the circuit is built using standard silicon integrated circuits, its speed amounts to several hundred megahertz, if it is constructed using gallium arsenide integrated circuits, its speed is several gigahertz.

  10. Semiconductor crystal high resolution imager

    Levin, Craig S. (Inventor); Matteson, James (Inventor)


    A radiation imaging device (10). The radiation image device (10) comprises a subject radiation station (12) producing photon emissions (14), and at least one semiconductor crystal detector (16) arranged in an edge-on orientation with respect to the emitted photons (14) to directly receive the emitted photons (14) and produce a signal. The semiconductor crystal detector (16) comprises at least one anode and at least one cathode that produces the signal in response to the emitted photons (14).

  11. Encapsulation, protection, and release of hydrophilic active components: potential and limitations of colloidal delivery systems.

    McClements, David Julian


    There have been major advances in the development of edible colloidal delivery systems for hydrophobic bioactives in recent years. However, there are still many challenges associated with the development of effective delivery systems for hydrophilic bioactives. This review highlights the major challenges associated with developing colloidal delivery systems for hydrophilic bioactive components that can be utilized in foods, pharmaceuticals, and other products intended for oral ingestion. Special emphasis is given to the fundamental physicochemical phenomena associated with encapsulation, stabilization, and release of these bioactive components, such as solubility, partitioning, barriers, and mass transport processes. Delivery systems suitable for encapsulating hydrophilic bioactive components are then reviewed, including liposomes, multiple emulsions, solid fat particles, multiple emulsions, biopolymer particles, cubosomes, and biologically-derived systems. The advantages and limitations of each of these delivery systems are highlighted. This information should facilitate the rational selection of the most appropriate colloidal delivery systems for particular applications in the food and other industries.

  12. Magnetic properties of carbon-encapsulated Fe-Co alloy nanoparticles.

    Wu, Aibing; Yang, Xuwei; Yang, Hua


    Carbon-encapsulated Fe-Co alloy nanoparticles (Fe-Co(C)) have been fabricated with different Co/Fe ratios by an efficient solid-state route using melamine as carbon source. The structure and morphology of Fe-Co(C) nanoparticles were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The XRD characterization results reveal that all products are alloys with no carbide impurity. The TEM and HRTEM observations show that the alloy nanoparticles are encapsulated in carbon shells. Additionally, the reactions involved in the syntheses are postulated. The variation of magnetic properties of Fe-Co(C) with Co/Fe has been discussed according to the room temperature VSM measurement results.

  13. Semiconductors for plasmonics and metamaterials

    Naik, G.V.; Boltasseva, Alexandra


    Plasmonics has conventionally been in the realm of metal-optics. However, conventional metals as plasmonic elements in the near-infrared (NIR) and visible spectral ranges suffer from problems such as large losses and incompatibility with semiconductor technology. Replacing metals with semiconduct......Plasmonics has conventionally been in the realm of metal-optics. However, conventional metals as plasmonic elements in the near-infrared (NIR) and visible spectral ranges suffer from problems such as large losses and incompatibility with semiconductor technology. Replacing metals...... with semiconductors can alleviate these problems if only semiconductors could exhibit negative real permittivity. Aluminum doped zinc oxide (AZO) is a low loss semiconductor that can show negative real permittivity in the NIR. A comparative assessment of AZO-based plasmonic devices such as superlens and hyperlens...... with their metal-based counterparts shows that AZO-based devices significantly outperform at a wavelength of 1.55 µm. This provides a strong stimulus in turning to semiconductor plasmonics at the telecommunication wavelengths. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)....

  14. Survey of cryogenic semiconductor devices

    Talarico, L.J.; McKeever, J.W.


    Improved reliability and electronic performance can be achieved in a system operated at cryogenic temperatures because of the reduction in mechanical insult and in disruptive effects of thermal energy on electronic devices. Continuing discoveries of new superconductors with ever increasing values of T{sub c} above that of liquid nitrogen temperature (LNT) have provided incentive for developing semiconductor electronic systems that may also operate in the superconductor`s liquid nitrogen bath. Because of the interest in high-temperature superconductor (HTS) devices, liquid nitrogen is the cryogen of choice and LNT is the temperature on which this review is focused. The purpose of this survey is to locate and assemble published information comparing the room temperature (298 K), performance of commercially available conventional and hybrid semiconductor device with their performance at LNT (77K), to help establish their candidacy as cryogenic electronic devices specifically for use at LNT. The approach to gathering information for this survey included the following activities. Periodicals and proceedings were searched for information on the behavior of semiconductor devices at LNT. Telephone calls were made to representatives of semiconductor industries, to semiconductor subcontractors, to university faculty members prominent for their research in the area of cryogenic semiconductors, and to representatives of the National Aeronautics and Space Administration (NASA) and NASA subcontractors. The sources and contacts are listed with their responses in the introduction, and a list of references appears at the end of the survey.

  15. Anisotropic silica mesostructures for DNA encapsulation

    Aparna Ganguly; Ashok K Ganguli


    The encapsulation of biomolecules in inert meso or nanostructures is an important step towards controlling drug delivery agents. Mesoporous silica nanoparticles (MSN) are of immense importance owing to their high surface area, large pore size, uniform particle size and chemical inertness. Reverse micellar method with CTAB as the surfactant has been used to synthesize anisotropic mesoporous silica materials. We have used the anisotropic silica nanostructures for DNA encapsulation studies and observed a loading capacity of ∼8 g mg-1 of the sample. On functionalizing the pores of silica with amine group, the amount of DNA loaded on the rods decreases which is due to a reduction in the pore size upon grafting of amine groups.

  16. Idiopathic sclerosing encapsulating peritonitis: Abdominal cocoon

    Jenny N Tannoury; Bassam N Abboud


    Abdominal cocoon,the idiopathic form of sclerosing encapsulating peritonitis,is a rare condition of unknown etiology that results in an intestinal obstruction due to total or partial encapsulation of the small bowel by a fibrocollagenous membrane.Preoperative diagnosis re quires a high index of clinical suspicion.The early clinical features are nonspecific,are often not recognized and it is difficult to make a definite pre-operative diagnosis.Clinical suspicion may be generated by the recurrent episodes of small intestinal obstruction combined with relevant imaging findings and lack of other plausible etiologies.The radiological diagnosis of abdominal cocoon may now be confidently made on computed tomography scan.Surgery is important in the management of this disease.Careful dissection and excision of the thick sac with the release of the small intestine leads to complete recovery in the vast majority of cases.

  17. Encapsulation of high temperature thermoelectric modules

    Salvador, James R.; Sakamoto, Jeffrey; Park, Youngsam


    A method of encapsulating a thermoelectric device and its associated thermoelectric elements in an inert atmosphere and a thermoelectric device fabricated by such method are described. These thermoelectric devices may be intended for use under conditions which would otherwise promote oxidation of the thermoelectric elements. The capsule is formed by securing a suitably-sized thin-walled strip of oxidation-resistant metal to the ceramic substrates which support the thermoelectric elements. The thin-walled metal strip is positioned to enclose the edges of the thermoelectric device and is secured to the substrates using gap-filling materials. The strip, substrates and gap-filling materials cooperatively encapsulate the thermoelectric elements and exclude oxygen and water vapor from atmospheric air so that the elements may be maintained in an inert, non-oxidizing environment.

  18. Nano-encapsulated PCM via Pickering Emulsification

    Wang, Xuezhen; Zhang, Lecheng; Yu, Yi-Hsien; Jia, Lisi; Sam Mannan, M.; Chen, Ying; Cheng, Zhengdong


    We designed a two-step Pickering emulsification procedure to create nano-encapsulated phase changing materials (NEPCMs) using a method whose simplicity and low energy consumption suggest promise for scale-up and mass production. Surface-modified amphiphilic zirconium phosphate (ZrP) platelets were fabricated as the Pickering emulsifiers, nonadecane was chosen as the core phase change material (PCM), and polystyrene, the shell material. The resultant capsules were submicron in size with remarkable uniformity in size distribution, which has rarely been reported. Differential scanning calorimetry (DSC) characterization showed that the capsulation efficiency of NEPCMs, and they were found to be thermal stable, as characterized by the DSC data for the sample after 200 thermal cycles. NEPCMs exhibit superior mechanical stability and mobility when compared with the well-developed micro-encapsulated phase change materials (MEPCMs). NEPCMs find useful applications in thermal management, including micro-channel coolants; solar energy storage media; building temperature regulators; and thermal transfer fabrics.

  19. Biexcitons in semiconductor microcavities

    Borri, Paola; Langbein, Wolfgang; Woggon, Ulrike; Esser, Axel; Jensen, Jacob R.; Hvam, Jørn M.


    In this paper, the present status of the experimental study of the optical properties of biexcitons in semiconductor microcavities is reviewed. In particular, a detailed investigation of a polariton-biexciton transition in a high-quality single quantum well GaAs/AlGaAs microcavity is reported. The binding energy and the coherent dynamics of the biexciton state are measured at low temperature using differential reflectivity and transient four-wave mixing spectroscopy, respectively. It is found that the biexciton binding energy is not strongly influenced by the exciton-photon coupling in the microcavity, even if the vacuum Rabi splitting exceeds the biexciton binding energy. However, the presence of a longitudinal built-in electric field that results in a Stark effect slightly reducing the binding energy compared to the value measured on a reference bare quantum well is experimentally pointed out and compared with calculations. Additionally, the polarization decay of the transition from the crystal ground state to the biexciton is measured and is shown to be larger by approximately a factor of two compared to the value measured on the reference quantum well.

  20. A semiconductor laser

    Naoko, O.; Khiroiti, S.


    An improved method is patented for increasing the service life of semiconductor lasers which does not hinder their characteristics, by applying a protective film to the end planes of the optical resonator of the laser. It is recommended that a mixture of an A1203 dielectric and an inert element such as argon be used for a GaAs, GaA1As laser as the protective film. The radii of gallium and arsenic atoms are equal to 1.24 and 1.25 angstroms, respectively. The radii of A1, O and Si atoms which make up the protective film are equal to 1.43, .61 and 1.17 angstroms, respectively. The radius of the argon atoms in the protective film, which is equal to 1.91 angstroms) is high compared to the atoms noted above. As a result, the movement of the gallium and arsenic atoms, which causes a drop in later characteristics during operation, is made more difficult.

  1. Cinnamomum casia Extract Encapsulated Nanochitosan as Antihypercholesterol

    Ngadiwiyana; Purbowatiningrum; Fachriyah, Enny; Ismiyarto


    Atherosclerosis vascular disease with clinical manifestations such as cardiovascular disease and stroke are the leading cause of death in Indonesia. One solution to these problems is a natural antihypercholesterol medicine by utilizing Cinnamomum casia extract. However, the use of natural extracts to lower blood cholesterol levels do not provide optimal results because it is possible that the active components of extract have been degraded/damaged during the absorption process. So that, we need to do the research to get a combination of chitosan nanoparticles-Cinnamomum casia. extract as a compound which has an antihypercholesterol activity through the in vitro study. Modification of natural extracts encapsulated nanochitosan be a freshness in this study, which were conducted using the method of inclusion. The combination of both has the dual function of protecting the natural extracts from degradation and deliver the natural extracts to the target site. Analysis of nanochitosan using the Particle Size Analyzer (PSA) shows the particle size of synthesis product that is equal to 64.9 nm. Encapsulation efficiency of Cinnamomum casia extract-Chitosan Nanoparticles known through UV-VIS spectrophotometry test and obtained the efficiency encapsulation percentage of 84.93%. Zeta Potential at 193,3 mv that chitosan appropriate for a delivery drug. Antihypercholesterol activity tested in vitro assay that showed the extract-nanoparticle chitosan in concentration 150 ppm gave the highest cholesterol decreasing level in the amount of 49.66% w/v. So it can be concluded that Cinnamomum casia extract can be encapsulated in nanoparticles of chitosan and proved that it has a cholesterol-lowering effect through the in vitro study.

  2. Carbon nanofibers encapsulated in macropores in silicon

    Starkov, V.; Red' kin, A. [Institute of Microelectronics Technology and High Purity Materials, RAS, Institutskaya str. 6, Chernogolovka 142432 (Russian Federation)


    This work reports on the development of fuel cells electrodes with a porous silicon structure and carbon nanofibers encapsulated in macropores in silicon. It is demonstrated that decomposition of carbon on a Ni catalyst deposited on the pore walls can be used to create a homogeneous carbon nanotube layer that dramatically increases the specific surface area while simultaneously reducing the resistivity of the macroporous silicon layer. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. PLGA microspheres encapsulating siRNA.

    De Rosa, Giuseppe; Salzano, Giuseppina


    The therapeutic use of small interfering RNA (siRNA) represents a new and powerful approach to suppress the expression of pathologically genes. However, biopharmaceutical drawbacks, such as short half-life, poor cellular uptake, and unspecific distribution into the body, hamper the development of siRNA-based therapeutics. Poly(lactide-co-glycolide), (PLGA) microspheres can be a useful tool to overcome these issues. siRNA can be encapsulated into the PLGA microspheres, which protects the loaded nucleic acid against the enzymatic degradation. Moreover, PLGA microspheres can be injected directly into the action site, where the siRNA can be released in controlled manner, thus avoiding the need of frequent invasive administrations. The complete biodegradability of PLGA to monomers easily metabolized by the body, and its approval by FDA and EMA for parenteral administration, assure the safety of this copolymer and do not require the removal of the device after the complete drug release. In chapter, a basic protocol for the preparation of PLGA microspheres encapsulating siRNA is described. This protocol is based on a double emulsion/solvent evaporation technique, a well known and easy to reproduce method. This specific protocol has been developed to encapsulate a siRNA anti-TNFα in PLGA microspheres, and it has been designed and optimized to achieve high siRNA encapsulation efficiency and slow siRNA release in vitro. However, it can be extended also to other siRNA as well as other RNA or DNA-based oligonucleotides (miRNA, antisense, decoy, etc.). Depending on the applications, chemical modifications of the backbone and site-specific modification within the siRNA sequences could be required.

  4. Encapsulating peritonitis: computed tomography and surgical correlation

    Kadow, Juliana Santos; Fingerhut, Carla Jeronimo Peres; Fernandes, Vinicius de Barros; Coradazzi, Klaus Rizk Stuhr; Silva, Lucas Marciel Soares; Penachim, Thiago Jose, E-mail: [Pontificia Universidade Catolica de Campinas (PUC-Campinas), Campinas, SP (Brazil). Hospital e Maternidade Celso Pierro


    Sclerosing encapsulating peritonitis is a rare and frequently severe entity characterized by total or partial involvement of small bowel loops by a membrane of fibrous tissue. The disease presents with nonspecific clinical features of intestinal obstruction, requiring precise imaging diagnosis to guide the treatment. The present report emphasizes the importance of computed tomography in the diagnosis of this condition and its confirmation by surgical correlation. (author)

  5. Tracking Hypoxic Signaling within Encapsulated Cell Aggregates

    Skiles, Matthew L.; Sahai, Suchit; Blanchette, James O.


    In Diabetes mellitus type 1, autoimmune destruction of the pancreatic β-cells results in loss of insulin production and potentially lethal hyperglycemia. As an alternative treatment option to exogenous insulin injection, transplantation of functional pancreatic tissue has been explored1,2. This approach offers the promise of a more natural, long-term restoration of normoglycemia. Protection of the donor tissue from the host's immune system is required to prevent rejection and encapsulation is...

  6. EDITORIAL: Oxide semiconductors

    Kawasaki, M.; Makino, T.


    Blue or ultraviolet semiconducting light-emitting diodes have the potential to revolutionize illumination systems in the near-future. Such industrial need has propelled the investigation of several wide-gap semiconducting materials in recent years. Commercial applications include blue lasers for DVD memory and laser printers, while military applications are also expected. Most of the material development has so far been focused on GaN (band gap 3.5 eV at 2 K), and ZnSe (2.9 eV) because these two representative direct transition semiconductors are known to be bright emitting sources. GaN and GaN-based alloys are emerging as the winners in this field because ZnSe is subject to defect formation under high current drive. On the other hand, another II-VI compound, ZnO, has also excited substantial interest in the optoelectronics-oriented research communities because it is the brightest emitter of all, owing to the fact that its excitons have a 60 meV binding energy. This is compared with 26 meV for GaN and 20 meV for ZnSe. The stable excitons could lead to laser action based on their recombination even at temperatures well above room temperature. ZnO has additional major properties that are more advantageous than other wide-gap materials: availability of large area substrates, higher energy radiation stability, environmentally-friendly ingredients, and amenability to wet chemical etching. However, ZnO is not new to the semiconductor field as exemplified by several studies made during the 1960s on structural, vibrational, optical and electrical properties (Mollwo E 1982 Landolt-Boernstein New Series vol 17 (Berlin: Springer) p 35). In terms of devices, the luminescence from light-emitting diode structures was demonstrated in which Cu2O was used as the p-type material (Drapak I T 1968 Semiconductors 2 624). The main obstacle to the development of ZnO has been the lack of reproducible p-type ZnO. The possibility of achieving epitaxial p-type layers with the aid of thermal

  7. 75 FR 49526 - Freescale Semiconductor, Inc., Technical Information Center, Tempe, AZ; Freescale Semiconductor...


    ... Employment and Training Administration Freescale Semiconductor, Inc., Technical Information Center, Tempe, AZ; Freescale Semiconductor, Inc., Technical Information Center, Woburn, MA; Amended Certification Regarding... Semiconductor, Inc., Technical Information Center, Tempe, Arizona. The notice was published in the...

  8. Ultrasonographic findings of sclerosing encapsulating peritonitis

    Han, Jong Kyu; Lee, Hae Kyung; Moon, Chul; Hong, Hyun Sook; Kwon, Kwi Hyang; Choi, Deuk Lin [Soonchunhyangi University College of Medicine, Seoul (Korea, Republic of)


    To evaluate the ultrasonographic findings of the patients with sclerosing encapsulating peritonitis (SEP). Thirteen patients with surgically confirmed sclerosing encapsulating peritonitis were involved in this study. Because of intestinal obstruction, all patients had received operations. Among 13 patients, 12 cases had continuous ambulatory peritoneal dialysis (CAPD) for 2 months-12 years and 4 months from (mean; 6 years and 10 months), owing to chronic renal failure and one patient had an operation due to variceal bleeding caused by liver cirrhosis. On ultrasonographic examination, all patients showed loculated ascites which were large (n=7) or small (n=6) in amount with multiple separations. The small bowel loops were tethered posteriorly perisaltic movement and covered with the thick membrane. The ultrasonographic of findings of sclerosing encapsulating peritonitis were posteriorly tethered small bowels covered with a thick membrane and loculated ascites with multiple septa. Ultrasonographic examination can detect the thin membrane covering the small bowel loops in the early phase of the disease, therefore ultrasonography would be a helpful modality to diagnose SEP early.

  9. Encapsulating peritonitis and familial Mediterranean fever

    Resat Dabak; Oya Uygur-Bayrami(c)li; Didem K1l1(c) Ayd1n; Can Dolap(c)1oglu; Cengiz Gemici; Turgay Erginel; Cem Turan; Nimet Karaday1


    AIM: To investigate the relationship between encapsulating peritonitis and familial Mediterranean fever (FMF). METHODS: The patient had a history of type 2 diabetes and laparoscopic cholecystectomy was performed one year ago for cholelithiasis. Eleven months after the operation she developed massive ascites. Biochemical evaluation revealed hyperglycemia, mild Fe deficiency anemia, hypoalbuminemia and a CA-125 level of 2 700 IU. Ascitic evaluation showed characteristics of exudation with a cell count of 580/mm3. Abdominal CT showed omental thickening and massive ascites. At exploratory laparotomy there was generalized thickening of the peritoneum and a laparoscopic clip encapsulated by fibrous tissue was found adherent to the uterus. Biopsies were negative for malignancy and a prophilactic total abdominal hysterectomy and bilateral salpingooophorectomy were performed. RESULTS: The histopathological evaluation was compatible with chronic nonspecific findings and mild mesothelial proliferation and chronic inflammation at the uterine serosa and liver biopsy showed inactive cirrhosis. CONCLUSION: The patient was evaluated as sclerosing encapsulating peritonitis induced by the laparoscopic clip acting as a foreign body. Due to the fact that the patient had FMF the immune response was probably exaggerated.

  10. Development of test models to quantify encapsulated bioburden in spacecraft polymer materials by cultivation-dependent and molecular methods

    Bauermeister, Anja; Moissl-Eichinger, Christine; Mahnert, Alexander; Probst, Alexander; Flier, Niwin; Auerbach, Anna; Weber, Christina; Haberer, Klaus; Boeker, Alexander

    Bioburden encapsulated in spacecraft polymers (such as adhesives and coatings) poses a potential risk to scientific exploration of other celestial bodies, but it is not easily detectable. In this study, we developed novel testing strategies to estimate the quantity of intrinsic encapsulated bioburden in polymers used frequently on spaceflight hardware. In particular Scotch-Weld (TM) 2216 B/A (Epoxy adhesive); MAP SG121FD (Silicone coating), Solithane (®) 113 (Urethane resin); ESP 495 (Silicone adhesive); and Dow Corning (®) 93-500 (Silicone encapsulant) were investigated. As extraction of bioburden from polymerized (solid) materials did not prove feasible, a method was devised to extract contaminants from uncured polymer precursors by dilution in organic solvents. Cultivation-dependent analyses showed less than 0.1-2.5 colony forming units (cfu) per cm³ polymer, whereas quantitative PCR with extracted DNA indicated considerably higher values, despite low DNA extraction efficiency. Results obtained by this method reflected the most conservative proxy for encapsulated bioburden. To observe the effect of physical and chemical stress occurring during polymerization on the viability of encapsulated contaminants, Bacillus safensis spores were embedded close to the surface in cured polymer, which facilitated access for different analytical techniques. Staining by AlexaFluor succinimidyl ester 488 (AF488), propidium monoazide (PMA), CTC (5-cyano-2,3-diotolyl tetrazolium chloride) and subsequent confocal laser scanning microscopy (CLSM) demonstrated that embedded spores retained integrity, germination and cultivation ability even after polymerization of the adhesive Scotch-Weld™ 2216 B/A.

  11. Synthesis and applications of heterostructured semiconductor nanocrystals

    Khon, Elena

    light emmision tunability. We reported a general strategy for the assembly of all-inorganic light-emitting nanocrystal films with an emission quantum yield in the 30-52% range. Our methodology relies on solution-processing of CdSe nanocrystals into a crystalline matrix of a wide band gap semiconductor (CdS, ZnS). As a result, we replace original organic ligands on nanocrystal surfaces with an inorganic medium which efficiently preserves the quantum confinement of electrical charges in CdSe NCs. In addition to strong emission, fabricated films demonstrated excellent thermal and chemical stability, and a large refractive index, which avails their integration into emerging solid-state nanocrystal devices. The ability to control size and shape of NCs is essential as it automatically affects the optoelectronic properties of the crystals. Colloidal chemistry offers an assortment of synthetic tools for tuning the shape of NCs, but some nanoparticle morphologies require alternative processing strategies. We have shown that chemical etching of colloidal nanoparticles can facilitate the realization of desirable nanocrystal geometries. This methodology allows both CdSe and CdS composed semiconductor domains be exposed to the external environment, while maintaining a structural design that is highly desirable for catalytic applications. Hydrogen production tests confirmed the improved catalytic activity of CdSe/CdS dimers. We expect that the demonstrated application will become a common methodology in the synthesis of charge-separating nanocrystals, leading to advanced nanoparticle architectures for applications in the areas of photocatalysis, photovoltaics, and light detection.

  12. Research of solid state recorder for spacecraft

    Shirakura, Masashi; Ichikawa, Satoshi; Sasada, Takeshi; Ohashi, Eiji; 白倉 政志; 市川 愉; 笹田 武志; 大橋 永嗣


    This research is to develop advanced, small, light-weight and low power consumption Solid State Recorder (SSR) on spacecraft utilizing the newest commercial semi-conductor memory device. We have manufactured, tested and evaluated next generation solid state recorder, researched high-efficient Error Detection And Correction code (EDAC). And also experimented and analyzed mission data of SSR on Mission Demonstration Satellite-1 (MDS-1) on orbit.

  13. Research of solid state recorder on spacecraft

    Ichikawa, Satoshi; Shirakura, Masashi; Sasada, Takeshi; 市川 愉; 白倉 政志; 笹田 武志


    This research is to develop advanced, small, light-weight and low power consumption solid state recorder (SSR) on spacecraft utilizing the newest commercial semi-conductor memory device. Next generation solid state recorder has been manufactured, tested and evaluated, high-efficient error detection and correction code (EDAC) have been researched, and also mission data of SSR on Mission Demonstration Satellite-1 (MDS-1) on orbit has been experimented and analyzed.

  14. Encapsulated, High-Performance, Stretchable Array of Stacked Planar Micro-Supercapacitors as Waterproof Wearable Energy Storage Devices.

    Kim, Hyoungjun; Yoon, Jangyeol; Lee, Geumbee; Paik, Seung-Ho; Choi, Gukgwon; Kim, Daeil; Kim, Beop-Min; Zi, Goangseup; Ha, Jeong Sook


    We report the fabrication of an encapsulated, high-performance, stretchable array of stacked planar micro-supercapacitors (MSCs) as a wearable energy storage device for waterproof applications. A pair of planar all-solid-state MSCs with spray-coated multiwalled carbon nanotube electrodes and a drop-cast UV-patternable ion-gel electrolyte was fabricated on a polyethylene terephthalate film using serial connection to increase the operation voltage of the MSC. Additionally, multiple MSCs could be vertically stacked with parallel connections to increase both the total capacitance and the areal capacitance owing to the use of a solid-state patterned electrolyte. The overall device of five parallel-connected stacked MSCs, a microlight-emitting diode (μ-LED), and a switch was encapsulated in thin Ecoflex film so that the capacitance remained at 82% of its initial value even after 4 d in water; the μ-LED was lit without noticeable decrease in brightness under deformation including bending and stretching. Furthermore, an Ecoflex encapsulated oximeter wound around a finger was operated using the stored energy of the MSC array attached to the hand (even in water) to give information on arterial pulse rate and oxygen saturation in the blood. This study suggests potential applications of our encapsulated MSC array in wearable energy storage devices especially in water.

  15. Semiconductor lasers stability, instability and chaos

    Ohtsubo, Junji


    This book describes the fascinating recent advances made concerning the chaos, stability and instability of semiconductor lasers, and discusses their applications and future prospects in detail. It emphasizes the dynamics in semiconductor lasers by optical and electronic feedback, optical injection, and injection current modulation. Applications of semiconductor laser chaos, control and noise, and semiconductor lasers are also demonstrated. Semiconductor lasers with new structures, such as vertical-cavity surface-emitting lasers and broad-area semiconductor lasers, are intriguing and promising devices. Current topics include fast physical number generation using chaotic semiconductor lasers for secure communication, development of chaos, quantum-dot semiconductor lasers and quantum-cascade semiconductor lasers, and vertical-cavity surface-emitting lasers. This fourth edition has been significantly expanded to reflect the latest developments. The fundamental theory of laser chaos and the chaotic dynamics in se...

  16. Ultraclean wafer-level vacuum-encapsulated silicon ring resonators for timing and frequency references

    Xereas, George; Chodavarapu, Vamsy P.


    We present the design and development of breath-mode silicon ring resonators fabricated using a commercial pure-play microfabrication process that provides ultraclean wafer-level vacuum-encapsulation. The micromechanical resonators are fabricated in MEMS integrated design for inertial sensors process that is developed by Teledyne DALSA Semiconductor Inc. The ring resonators are designed to operate with a relatively low DC polarization voltage, starting at 5 V, while providing a high frequency-quality factor product. We study the quality of the vacuum packaging using an automated testing setup over an extended time period. We study the effect of motional resistance on the performance of MEMS resonators. The fabricated devices had a resonant frequency of 10 MHz with the quality factor exceeding 8.4×104.

  17. Wide-Bandgap Semiconductors

    Chinthavali, M.S.


    With the increase in demand for more efficient, higher-power, and higher-temperature operation of power converters, design engineers face the challenge of increasing the efficiency and power density of converters [1, 2]. Development in power semiconductors is vital for achieving the design goals set by the industry. Silicon (Si) power devices have reached their theoretical limits in terms of higher-temperature and higher-power operation by virtue of the physical properties of the material. To overcome these limitations, research has focused on wide-bandgap materials such as silicon carbide (SiC), gallium nitride (GaN), and diamond because of their superior material advantages such as large bandgap, high thermal conductivity, and high critical breakdown field strength. Diamond is the ultimate material for power devices because of its greater than tenfold improvement in electrical properties compared with silicon; however, it is more suited for higher-voltage (grid level) higher-power applications based on the intrinsic properties of the material [3]. GaN and SiC power devices have similar performance improvements over Si power devices. GaN performs only slightly better than SiC. Both SiC and GaN have processing issues that need to be resolved before they can seriously challenge Si power devices; however, SiC is at a more technically advanced stage than GaN. SiC is considered to be the best transition material for future power devices before high-power diamond device technology matures. Since SiC power devices have lower losses than Si devices, SiC-based power converters are more efficient. With the high-temperature operation capability of SiC, thermal management requirements are reduced; therefore, a smaller heat sink would be sufficient. In addition, since SiC power devices can be switched at higher frequencies, smaller passive components are required in power converters. Smaller heat sinks and passive components result in higher-power-density power converters

  18. Solid on liquid deposition

    Charmet, J., E-mail: jerome.charmet@he-arc.c [Institut des Microtechnologies Appliquees ARC, HES-SO Arc, Eplatures-Grise 17, 2300 La Chaux-de-Fonds (Switzerland); Banakh, O.; Laux, E.; Graf, B.; Dias, F.; Dunand, A.; Keppner, H. [Institut des Microtechnologies Appliquees ARC, HES-SO Arc, Eplatures-Grise 17, 2300 La Chaux-de-Fonds (Switzerland); Gorodyska, G.; Textor, M. [BioInterface group, ETHZ, Wolfgang-Pauli-Strasse 10, ETH Hoenggerberg HCI H 525 8093 Zuerich (Switzerland); Noell, W.; Rooij, N.F. de [Ecole Polytechnique Federale de Lausanne, Institute of Microengineering, Sensors, Actuators and Microsystems laboratory, Rue Jaquet Droz 1, 2000 Neuchatel (Switzerland); Neels, A.; Dadras, M.; Dommann, A.; Knapp, H. [Centre Suisse d' Electronique et de Microtechnique SA, Rue Jacquet-Droz 1, 2002 Neuchatel (Switzerland); Borter, Ch.; Benkhaira, M. [COMELEC SA, Rue de la Paix 129, 2300 La Chaux-de-Fonds (Switzerland)


    A process for the deposition of a solid layer onto a liquid is presented. The polymer poly-di-chloro-para-xylylene, also known as Parylene C, was grown on low vapour pressure liquids using the conventional low pressure chemical vapour deposition process. A reactor was built and a process developed to enable the deposition of Parylene C at atmospheric pressure over high vapour pressure liquids. It was used to deposit Parylene C over water among others. In all cases Parylene C encapsulated the liquid without influencing its initial shape. The results presented here show also that the Parylene C properties are not affected by its growth on liquid templates and the roughness of the Parylene C surface in contact with the liquid during the deposition is extremely low.

  19. Dielectric screening in semiconductors

    Harrison, Walter A.; Klepeis, John E.


    Intra-atomic and interatomic Coulomb interactions are incorporated into bond-orbital theory, based upon universal tight-binding parameters, in order to treat the effects of charge redistribution in semiconductor bonds. The dielectric function ɛ(q) is obtained for wave numbers in a [100] direction. The screening of differences in average hybrid energy across a heterojunction is calculated in detail, indicating that the decay length for the potential depends upon the relative values of Madelung and intra-atomic Coulomb terms. The parameters used here predict an imaginary decay length and thus an oscillating potential near the interface. The same theory is applied to point defects by imbedding a cluster in a matrix lattice, taking charges in that lattice to be consistent with continuum theory. Illustrating the theory with a phosphorus impurity in silicon, it is seen that the impurity and its neighboring atoms have charges on the order of only one-tenth of an electronic charge, alternating in sign from neighbor to neighbor as for planar defects. Although there are shifts in the term values on the order of a volt, the difference in these shifts for neighboring atoms is much smaller so that the effect on the bonds is quite small. This behavior is analogous to the response of a dielectric continuum to a point charge: The medium is locally neutral except at the center of the cluster and there are slowly varying potentials e2/ɛr. Because of this slow variation, free-atom term values should ordinarily suffice for the calculation of bond properties and bond lengths at impurities. Corrections are larger for homovalent substitutions such as carbon in silicon.

  20. Solid-State Neutron Detector Device

    Bensaoula, Abdelhak (Inventor); Starikov, David (Inventor); Pillai, Rajeev (Inventor)


    The structure and methods of fabricating a high efficiency compact solid state neutron detector based on III-Nitride semiconductor structures deposited on a substrate. The operation of the device is based on absorption of neutrons, which results in generation of free carriers.

  1. Crystal orbital study on the double walls made of nanotubes encapsulated inside zigzag carbon nanotubes

    Zhao, Xin [College of Chemistry, Beijing Normal University, Beijing 100875 (China); Qiao, Weiye [College of Chemical Engineering and Biological Technology, Xingtai University, Xingtai 054001 (China); Li, Yuliang [College of Chemistry, Beijing Normal University, Beijing 100875 (China); Huang, Yuanhe, E-mail: [College of Chemistry, Beijing Normal University, Beijing 100875 (China)


    The structure stabilities and electronic properties are investigated by using ab initio self-consistent-field crystal orbital method based on density functional theory for the one-dimensional (1D) double-wall nanotubes made of n-gon SiO{sub 2} nanotubes encapsulated inside zigzag carbon nanotubes. It is found that formation of the combined systems is energetically favorable when the distance between the two constituents is around the Van der Waals scope. The obtained band structures show that all the combined systems are semiconductors with nonzero energy gaps. The frontier energy bands (the highest occupied band and the lowest unoccupied band) of double-wall nanotubes are mainly derived from the corresponding carbon nanotubes. The mobilities of charge carriers are calculated to be within the range of 10{sup 2}–10{sup 4} cm{sup 2} V{sup −1} s{sup −1} for the hybrid double-wall nanotubes. Young’s moduli are also calculated for the combined systems. For the comparison, geometrical and electronic properties of n-gon SiO{sub 2} nanotubes are also calculated and discussed. - Graphical abstract: Structures and band structures of the optimum 1D Double walls nanotubes. The optimized structures are 3-gon SiO2@(15,0), 5-gon SiO2@(17,0), 6-gon SiO2@(18,0) and 7-gon SiO2@(19,0). - Highlights: • The structure and electronic properties of the 1D n-gon SiO{sub 2}@(m,0)s are studied using SCF-CO method. • The encapsulation of 1D n-gon SiO{sub 2} tubes inside zigzag carbon nanotubes can be energetically favorable. • The 1D n-gon SiO{sub 2}@(m,0)s are all semiconductors. • The mobility of charge carriers and Young’s moduli are calculated.

  2. Refractive Indices of Semiconductors from Energy gaps

    Tripathy, S K


    An empirical relation based on energy gap and refractive index data has been proposed in the present study to calculate the refractive index of semiconductors. The proposed model is then applied to binary as well as ternary semiconductors for a wide range of energy gap. Using the relation, dielectric constants of some III-V group semiconductors are calculated. The calculated values for different group of binary semiconductors, alkali halides and ternary semiconductors fairly agree with other calculations and known values over a wide range of energy gap. The temperature variation of refractive index for some binary semiconductors have been calculated.

  3. Semiconductors for solar cell applications

    Moeller, H.J. (Case Western Reserve Univ., Cleveland, OH (United States). Dept. of Materials Science and Engineering)


    This review covers the historical background of the solar cell development, the physical principles of photovoltaic energy conversion, technology of solar cell devices and the structural and physical properties of lattice defects in semiconductors. Single crystal and polycrystalline silicon, single crystal and epitaxial gallium arsenide, polycrystalline thin films and amorphous thin films are discussed in detail. Semiconductors have emerged as the most promising group of materials which can convert sunlight directly into electrical energy. They utilize the fundamental physical process that a photon that penetrates into the semiconductor and is absorbed can generate electron-hole pairs. Because of their opposite charges they can be separated by an internal electrical field and collected at two contacts thus giving rise to a voltage and photocurrent if the two contacts are connected externally. In semiconductors internal electric fields occur in connection with space charges at junctions and a variety of technological concepts are used to produce a built-in voltage. The most widely used device principle is the operation of a solar cell as a diode or p-n junction. Alternative concepts are heterojunction devices where the materials on either side of the junction are different semiconductors. (author).

  4. Closing photoconductive semiconductor switches

    Loubriel, G.M.; Zutavern, F.J.; Hjalmarson, H.P.; O' Malley, M.W.


    One of the most important limitations of Photoconductive Semiconductor Switches (PCSS) for pulsed power applications is the high laser powers required to activate the switches. In this paper, we discuss recent developments on two different aspects of GaAs PCSS that result in reductions in laser power by a factor of nearly 1000. The advantages of using GaAs over Si are many. First of all, the resistivity of GaAs can be orders of magnitude higher than that of the highest resistivity Si material, thus allowing GaAs switches to withstand dc voltages without thermal runaway. Secondly, GaAs has a higher carrier mobility than Si and, thus, is more efficient (per carrier). Finally, GaAs switches can have naturally fast (ns) opening times at room temperature and low fields, microsecond opening times at liquid nitrogen temperature of 77 K, or, on demand, closing and opening at high fields and room temperature by a mechanism called lock-on (see Ref. 1). By contrast, Si switches typically opening times of milliseconds. The amount of laser light required to trigger GaAs for lock-on, or at 77 K, is about three orders of magnitude lower than at room temperature. In this paper we describe the study of lock-on in GaAs and InP, as well as switching of GaAs at 77 K. We shall show that when GaAs is switched at 77 K, the carrier lifetime is about three orders of magnitude longer than it is at room temperature. We shall explain the change in lifetime in terms of the change in electron capture cross section of the deep levels in GaAs (these are defect or impurity levels in the band gap). In the second section, we describe the lock-on effect, now seen in GaAs and InP, and at fields as high as 70 kV/cm. We show how lock-on can be tailored by changing the GaAs temperature or by neutron bombardment. In the third section, we discuss possible lock-on mechanisms. 5 refs., 5 figs.

  5. Catalysts, Protection Layers, and Semiconductors

    Chorkendorff, Ib


    Hydrogen is the simplest solar fuel to produce and in this presentation we shall give a short overview of the pros and cons of various tandem devices [1]. The large band gap semiconductor needs to be in front, but apart from that we can chose to have either the anode in front or back using either...... acid or alkaline conditions. Since most relevant semiconductors are very prone to corrosion the advantage of using buried junctions and using protection layers offering shall be discussed [2-4]. Next we shall discuss the availability of various catalysts for being coupled to these protections layers...... and how their stability may be evaluated [5, 6]. Examples of half-cell reaction using protection layers for both cathode and anode will be discussed though some of recent examples under both alkaline and acidic conditions. Si is a very good low band gap semiconductor and by using TiO2 as a protection...

  6. High pressure semiconductor physics I

    Willardson, R K; Paul, William; Suski, Tadeusz


    Since its inception in 1966, the series of numbered volumes known as Semiconductors and Semimetals has distinguished itself through the careful selection of well-known authors, editors, and contributors. The "Willardson and Beer" Series, as it is widely known, has succeeded in publishing numerous landmark volumes and chapters. Not only did many of these volumes make an impact at the time of their publication, but they continue to be well-cited years after their original release. Recently, Professor Eicke R. Weber of the University of California at Berkeley joined as a co-editor of the series. Professor Weber, a well-known expert in the field of semiconductor materials, will further contribute to continuing the series' tradition of publishing timely, highly relevant, and long-impacting volumes. Some of the recent volumes, such as Hydrogen in Semiconductors, Imperfections in III/V Materials, Epitaxial Microstructures, High-Speed Heterostructure Devices, Oxygen in Silicon, and others promise indeed that this tra...

  7. Organic Semiconductors and its Applications

    Kamalasanan, M. N.


    Organic semiconductors in the form of evaporated or spin coated thin films have many optoelectronic applications in the present electronic industry. They are frequently used in many type of displays, photo detectors, photoconductors for photocopiers and photovoltaic cells. But many p-conjugated molecules and polymer based devices do not provide satisfactory device performance and operational stability. Most of these problems are related to the interfaces they make with other organic materials and electrodes and the low conductivity of the organic layers. The study of organic-metal and organic—organic interfaces as well as electrical doping of organic semiconductors are very important areas of research at present. In this talk, I will be discussing some of the recent advances in this field as well as some of our own results in the area of interface modification and electrical doping of organic semiconductors.

  8. Thermoresponsive latexes for fragrance encapsulation and release.

    Popadyuk, N; Popadyuk, A; Kohut, A; Voronov, A


    To synthesize cross-linked latex particles protecting the encapsulated fragrance at ambient temperatures and facilitating the release of cargo at the temperature of the surface of the skin that varies in different regions of the body between 33.5 and 36.9°C. Poly(stearyl acrylate) (PSA), a polymer with long crystallizable alkyl side chains (undergoes order-disorder transitions at 45°C), was chosen as the main component of the polymer particles. As a result, new thermoresponsive polymer particles for fragrance encapsulation were synthesized and characterized, including assessing the performance of particles in triggered release by elevated temperature. To obtain network domains of various crystallinity, stearyl acrylate was copolymerized with dipropylene glycol acrylate caprylate (DGAC) (comonomer) in the presence of a dipropylene glycol diacrylate sebacate (cross-linker) using the miniemulsion process. Comonomers and a cross-linker were mixed directly in a fragrance during polymerization. Fragrance release was evaluated at 25, 31, 35 and 39°C to demonstrate a new material potential in personal/health care skin-related applications. Particles protect the fragrance from evaporation at 25°C. The fragrance release rate gradually increases at 31, 35 and 39°C. Two slopes were found on release plots. The first slope corresponds to a rapid fragrance release. The second slope indicates a subsequent reduction in the release rate. Crystalline-to-amorphous transition of PSA triggers the release of fragrances from cross-linked latex particles at elevated temperatures. The presence of the encapsulated fragrance, as well as the inclusion of amorphous fragments in the polymer network, reduces the particle crystallinity and enhances the release. Release profiles can be tuned by temperature and controlled by the amount of loaded fragrance and the ratio of comonomers in the feed mixture. © 2015 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  9. Exciton Transport in Organic Semiconductors

    Menke, Stephen Matthew

    Photovoltaic cells based on organic semiconductors are attractive for their use as a renewable energy source owing to their abundant feedstock and compatibility with low-cost coating techniques on flexible substrates. In contrast to photovoltaic cells based traditional inorganic semiconductors, photon absorption in an organic semiconductor results in the formation of a coulombically bound electron-hole pair, or exciton. The transport of excitons, consequently, is of critical importance as excitons mediate the interaction between charge and light in organic photovoltaic cells (OPVs). In this dissertation, a strong connection between the fundamental photophysical parameters that control nanoscopic exciton energy transfer and the mesoscopic exciton transport is established. With this connection in place, strategies for enhancing the typically short length scale for exciton diffusion (L D) can be developed. Dilution of the organic semiconductor boron subphthalocyanine chloride (SubPc) is found to increase the LD for SubPc by 50%. In turn, OPVs based on dilute layers of SubPc exhibit a 30% enhancement in power conversion efficiency. The enhancement in power conversion efficiency is realized via enhancements in LD, optimized optical spacing, and directed exciton transport at an exciton permeable interface. The role of spin, energetic disorder, and thermal activation on L D are also addressed. Organic semiconductors that exhibit thermally activated delayed fluorescence and efficient intersystem and reverse intersystem crossing highlight the balance between singlet and triplet exciton energy transfer and diffusion. Temperature dependent measurements for LD provide insight into the inhomogeneously broadened exciton density of states and the thermal nature of exciton energy transfer. Additional topics include energy-cascade OPV architectures and broadband, spectrally tunable photodetectors based on organic semiconductors.

  10. Characterization of defects in semiconductors using radioactive isotopes

    Deicher, Manfred


    Radioactive atoms have been used in solid-state physics and in material science for many decades. Besides their classical application as tracer for diffusion studies, nuclear techniques such as Mossbauer spectroscopy, perturbed angular correlation, and emission channeling have used nuclear properties to gain microscopical information on the structural and dynamical properties of solids. The availability of many different radioactive isotopes as a clean ion beam at facilities like ISOLDE/CERN has triggered a new era involving methods sensitive for the optical and electronic properties of solids, especially in the field of semiconductor physics. Spectroscopic techniques like photoluminescence (PL), deep-level transient spectroscopy (DLTS), and Hall effect gain a new quality by using radioactive isotopes. Due to their decay the chemical origin of an observed electronic and optical behavior of a specific defect or dopant can be unambiguously identified. This contribution will highlight a few examples to illustrat...

  11. Computed tomography appearances of sclerosing encapsulating peritonitis

    George, C. [Department of Radiology, Hull Royal Infirmary, Hull (United Kingdom)]. E-mail:; Al-Zwae, K. [Department of Radiology, Hull Royal Infirmary, Hull (United Kingdom); Nair, S. [Department of Radiology, Hull Royal Infirmary, Hull (United Kingdom); Cast, J.E.I. [Department of Radiology, Hull Royal Infirmary, Hull (United Kingdom)


    Sclerosing encapsulating peritonitis (SEP) is a serious complication of peritoneal dialysis (PD) characterized by thickened peritoneal membranes, which lead to decreased ultra-filtration and intestinal obstruction. Its early clinical features are nonspecific, and it is often diagnosed late following laparotomy and peritoneal biopsy, when the patient develops small bowel obstruction, which can be a life-threatening complication. However, this is changing with increasing awareness of computed tomography (CT) findings in SEP. CT can yield an early, non-invasive diagnosis that may improve patient outcome. We present a review of the CT appearances of SEP.

  12. Stabilization and encapsulation of magnetite nanoparticles

    Kawni, Issmat Al; Garcia, Ricardo; Youssef, Sami; Abboud, Maher; Podlecki, Jean; Habchi, Roland


    The goal is to stabilize magnetite nanoparticles (NPs) in order to prepare them for encapsulation and to obtain a core–shell structure. Magnetite NPs were obtained by a co-precipitation method and then treated with different stabilizing agents in order to get a full dispersion in an aqueous medium. The dispersed particles were then coated with silica using a TEOS solution. The samples were characterized by Raman spectroscopy, TEM, EDX analysis, and FTIR measurements. The particles are the basis of a core–shell structure where a potential polymer or drug could be anchored on the surface.

  13. Research on Rare Earth Encapsulated Luminescent Material

    Yu Zhiwei; Liu Chengdong; Qi Xiaopeng


    A new method of preparation of irradiative material by using rare earth as luminophor and inorganic powder as base nucleus was presented.Rare earth was used to make colloid, which was mixed with base nucleus solution,where deposition/attachment reaction took place and rare earth was adhered onto the surface of base nucleus, hence yielding a new rare earth encapsulated irradiative material.Fluorescent spectrum analysis shows that this material possesses two emission peaks, one within 400 ~ 500 nm and the other within 580 ~ 700 nm, reflecting the luminous characteristics of original rare earth material.

  14. Encapsulation of testosterone by chitosan nanoparticles.

    Chanphai, P; Tajmir-Riahi, H A


    The loading of testosterone by chitosan nanoparticles was investigated, using multiple spectroscopic methods, thermodynamic analysis, TEM images and modeling. Thermodynamic parameters showed testosterone-chitosan bindings occur mainly via H-bonding and van der Waals contacts. As polymer size increased more stable steroid-chitosan conjugates formed and hydrophobic contact was also observed. The loading efficacy of testosterone-nanocarrier was 40-55% and increased as chitosan size increased. Testosterone encapsulation markedly alters chitosan morphology. Chitosan nanoparticles are capable of transporting testosterone in vitro. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. High solids loading of aluminum nitride powder in epoxy resin: Dispersion and thermal conductivity

    Lee, Eunsung

    Most semiconductor devices are now packaged in an epoxy polymer composite, which includes a silica powder filler for reducing the thermal expansion coefficient. However, increased heat output from near-future semiconductors will require higher thermal conductivity fillers such as aluminum nitride powder, instead of silica. This thesis research is intended to apply improved dispersant chemistry, in order to achieve a high volume percentage of AlN powder in epoxy, increasing the thermal conductivity of the composite without causing excessive viscosity before the epoxy monomer is crosslinked. In initial experiments, the dispersibility of aluminum oxide in epoxy monomer resin was better than that of AlN, because of the weaker basicity of oxide surfaces compared with nitride. To improve the dispersibility of AlN, its surface was modified by pretreatment with silane coupling agents. Silane molecules with different head groups were investigated. In those experiments, methylsilane gave lower viscosities than chloro- or methoxysilane, while pretreatments using organic acids increased the viscosity of the AlN dispersion. The viscosity changes and FTIR peak intensity trends suggested that the silane molecules could be adsorbed on AlN surfaces in the form of a monolayer during optimization experiments, and the best silane monolayer coverage on the AlN powder surfaces was achieved with 2 wt% amounts in a 3 hour treatment. A particular phosphate ester was a good second layer dispersant for the AlN-plus-epoxy system. When that dispersant was added onto the silane-treated filler surfaces, the degree of viscosity reduction was dependent on the types of silane coupling agent functional groups. In the optimized results, silane pretreatment followed by dispersant addition was better than either alone. High solids loading, up to 57 vol.%, was achieved with a wide particle size distribution of powder, and the viscosity of that dispersion was 60,000 to 90,000 cps, which easily flowed by

  16. Closantel nano-encapsulated polyvinyl alcohol (PVA) solutions.

    Vega, Abraham Faustino; Medina-Torres, Luis; Calderas, Fausto; Gracia-Mora, Jesus; Bernad-Bernad, MaJosefa


    The influence of closantel on the rheological and physicochemical properties (particle size and by UV-Vis absorption spectroscopy) of PVA aqueous solutions is studied here. About 1% PVA aqueous solutions were prepared by varying the closantel content. The increase of closantel content led to a reduction in the particle size of final solutions. All the solutions were buffered at pH 7.4 and exhibited shear-thinning behavior. Furthermore, in oscillatory flow, a "solid-like" type behavior was observed for the sample containing 30 μg/mL closantel. Indicating a strong interaction between the dispersed and continuous phases and evidencing an interconnected network between the nanoparticle and PVA, this sample also showed the highest shear viscosity and higher shear thinning slope, indicating a more intrincate structure disrupted by shear. In conclusion, PVA interacts with closantel in aqueous solution and the critical concentration for closantel encapsulation by PVA was about 30 μg/mL; above this concentration, the average particle size decreased notoriously which was associated to closantel interacting with the surface of the PVA aggregates and thus avoiding to some extent direct polymer-polymer interaction.

  17. Neural probe design for reduced tissue encapsulation in CNS.

    Seymour, John P; Kipke, Daryl R


    This study investigated relationships between a microscale neural probe's size and shape and its chronic reactive tissue response. Parylene-based probes were microfabricated with a thick shank (48 microm by 68 microm) and an integrated thin lateral platform (5 microm by 100 microm, either solid or one of three lattice sizes). Devices were implanted in rat cerebral cortex for 4 weeks before immunostaining for neurons, astrocytes, microglia, fibronectin, laminin, and neurofilament. While nonneuronal density (NND) generally increased and neuronal density decreased within 75 microm of a probe interface compared to unimplanted control regions, there were significant differential tissue responses within 25 microm of the platform's lateral edge compared to the shank. The NND in this region of the lateral edge was less than one-third of the corresponding region of the shank (129% and 425% increase, respectively). Moreover, neuronal density around the platform lateral edge was about one-third higher than at the shank (0.70 and 0.52 relative to control, respectively). Also, microglia reactivity and extracellular protein deposition was reduced at the lateral edge. There were no significant differences among platform designs. These results suggest that neural probe geometry is an important parameter for reducing chronic tissue encapsulation.

  18. Photovoltaic module encapsulation design and materials selection. Volume II

    Cuddihy, E.


    This is Volume II of Photovoltaic Module Encapsulation Design and Materials Selection: a periodically updated handbook of encapsulation technology, developed with the support of the Flat-Plate Solar Array Project (FSA), managed for the Department of Energy (DOE) by the Jet Propulsion Laboratory. Volume II describes FSA encapsulation technology developed between June 1, 1982, and January 1, 1984. Emphasis during this period shifted from materials development to demonstration of reliability and durability in an outdoor environment; the updated information in this volume reflects the developing technology base related to both reliability and encapsulation process improvements.

  19. Durability of Polymeric Encapsulation Materials for Concentrating Photovoltaic Systems (Poster)

    Miller, D. C.; Kempe, M. D.; Araki, K.; Kennedy, C. E.; Kurtz, S. R.


    Polymeric encapsulation materials are typically used in concentrating photovoltaic (CPV) modules to protect the cell from the field environment. Because it is physically located adjacent to the cell, the encapsulation is exposed to a high optical flux, often including light in the ultraviolet (UV) and infrared (IR) wavelengths. The durability of encapsulants used in CPV modules is critical to the technology, but is presently not well understood. This work seeks to identify the appropriate material types, field-induced failure mechanisms, and factors of influence (if possible) of polymeric encapsulation. These results will ultimately be weighed against those of future qualification and accelerated life test procedures.

  20. The Novel Semiconductor Nanowire Heterostructures

    J.Q.Hu; Y.Bando; J.H.Zhan; D.Golberg


    1 Results If one-dimensional heterostructures with a well-defined compositional profile along the wire radial or axial direction can be realized within semiconductor nanowires, new nano-electronic devices,such as nano-waveguide and nano-capcipator, might be obtained. Here,we report the novel semiconducting nanowire heterostructures:(1) Si/ZnS side-to-side biaxial nanowires and ZnS/Si/ZnS sandwich-like triaxial nanowires[1],(2) Ga-Mg3N2 and Ga-ZnS metal-semiconductor nanowire heterojunctions[2-3]and (3) ...

  1. Modeling of semiconductor optical amplifiers

    Mørk, Jesper; Bischoff, Svend; Berg, Tommy Winther

    We discuss the modelling of semiconductor optical amplifiers with emphasis on their high-speed properties. Applications in linear amplification as well as ultrafast optical signal processing are reviewed. Finally, the possible role of quantum-dot based optical amplifiers is discussed.......We discuss the modelling of semiconductor optical amplifiers with emphasis on their high-speed properties. Applications in linear amplification as well as ultrafast optical signal processing are reviewed. Finally, the possible role of quantum-dot based optical amplifiers is discussed....

  2. Organic semiconductors in sensor applications

    Malliaras, George; Owens, Róisín


    Organic semiconductors offer unique characteristics such as tunability of electronic properties via chemical synthesis, compatibility with mechanically flexible substrates, low-cost manufacturing, and facile integration with chemical and biological functionalities. These characteristics have prompted the application of organic semiconductors and their devices in physical, chemical, and biological sensors. This book covers this rapidly emerging field by discussing both optical and electrical sensor concepts. Novel transducers based on organic light-emitting diodes and organic thin-film transistors, as well as systems-on-a-chip architectures are presented. Functionalization techniques to enhance specificity are outlined, and models for the sensor response are described.

  3. Introduction to semiconductor manufacturing technology


    IC chip manufacturing processes, such as photolithography, etch, CVD, PVD, CMP, ion implantation, RTP, inspection, and metrology, are complex methods that draw upon many disciplines. [i]Introduction to Semiconductor Manufacturing Technologies, Second Edition[/i] thoroughly describes the complicated processes with minimal mathematics, chemistry, and physics; it covers advanced concepts while keeping the contents accessible to readers without advanced degrees. Designed as a textbook for college students, this book provides a realistic picture of the semiconductor industry and an in-depth discuss

  4. Semiconductors and semimetals epitaxial microstructures

    Willardson, Robert K; Beer, Albert C; Gossard, Arthur C


    Newly developed semiconductor microstructures can now guide light and electrons resulting in important consequences for state-of-the-art electronic and photonic devices. This volume introduces a new generation of epitaxial microstructures. Special emphasis has been given to atomic control during growth and the interrelationship between the atomic arrangements and the properties of the structures.Key Features* Atomic-level control of semiconductor microstructures* Molecular beam epitaxy, metal-organic chemical vapor deposition* Quantum wells and quantum wires* Lasers, photon(IR)detectors, heterostructure transistors

  5. Quantum Transport in Semiconductor Devices


    TITLE AND SUBTITLE S. FUNDING NUMBERS " Quantum Transport in Semiconductor Devices" 6. AUTHOR(S) ,DftftLo3-91-6-oo 7 David K. Ferry 7. PERFORMING...OF ABSTRACT UNCLASSIFIED UNCLASSIFIED UNCLASSIFIED UL NZIN 1540-01-280-5500 Standard Form 298 (Rev 2-89) PrinCrlt>• oy ANSI SIC Z39-18 QUANTUM ... TRANSPORT IN SEMICONDUCTOR DEVICES Final Report on DAAL03-91-G-0067 (28461-EL) David K. Ferry, Principal Investigator Department of Electrical Engineering

  6. Nonlinear Peltier effect in semiconductors

    Zebarjadi, Mona; Esfarjani, Keivan; Shakouri, Ali


    Nonlinear Peltier coefficient of a doped InGaAs semiconductor is calculated numerically using the Monte Carlo technique. The Peltier coefficient is also obtained analytically for single parabolic band semiconductors assuming a shifted Fermi-Dirac electronic distribution under an applied bias. Analytical results are in agreement with numerical simulations. Key material parameters affecting the nonlinear behavior are doping concentration, effective mass, and electron-phonon coupling. Current density thresholds at which nonlinear behavior is observable are extracted from numerical data. It is shown that the nonlinear Peltier effect can be used to enhance cooling of thin film microrefrigerator devices especially at low temperatures.

  7. The processing of semiconductor materials


    Five experiments involving the processing of semiconductor materials were performed during the Skylab mission. After discussions on semiconductors and their unique electronic properties, and techniques of crystal growth, these five experiments are presented. Four melt growth experiments were attempted: (1) steady state growth and segregation under zero gravity (InSb); (2) seeded, containerless solidification of InSb; (3) influence of gravity-free solidification on microsegregation; and (4) directional solidification of InSb-GaSb alloys. One vapor growth experiment, crystal growth by vapor transport, was attempted.

  8. Building a spin quantum bit register using semiconductor nanowires.

    Baugh, J; Fung, J S; Mracek, J; LaPierre, R R


    This paper reviews recent advances in engineering spin quantum bits (qubits) in semiconductor quantum dots and describes an approach based on top-gated semiconductor nanowire devices. Fast electrical single-spin manipulation is achievable, in principle, using the spin-orbit interaction intrinsic to III-V materials, such as InAs, in concert with AC electric fields. Combined with sub-nanosecond gate control of the nearest-neighbor exchange interaction and spin readout by spin-to-charge conversion, a fully electrical solid-state quantum processor is within reach. We outline strategies for spin manipulation, robust readout and mitigation of decoherence due to nuclear fields that, when combined in a single device, should give a viable multi-qubit testbed and a building block for larger scale quantum devices.

  9. Optical switching of nuclear spin-spin couplings in semiconductors.

    Goto, Atsushi; Ohki, Shinobu; Hashi, Kenjiro; Shimizu, Tadashi


    Two-qubit operation is an essential part of quantum computation. However, solid-state nuclear magnetic resonance quantum computing has not been able to fully implement this functionality, because it requires a switchable inter-qubit coupling that controls the time evolutions of entanglements. Nuclear dipolar coupling is beneficial in that it is present whenever nuclear-spin qubits are close to each other, while it complicates two-qubit operation because the qubits must remain decoupled to prevent unwanted couplings. Here we introduce optically controllable internuclear coupling in semiconductors. The coupling strength can be adjusted externally through light power and even allows on/off switching. This feature provides a simple way of switching inter-qubit couplings in semiconductor-based quantum computers. In addition, its long reach compared with nuclear dipolar couplings allows a variety of options for arranging qubits, as they need not be next to each other to secure couplings.

  10. Semiconductor ferroelectric compositions and their use in photovoltaic devices

    Rappe, Andrew M; Davies, Peter K; Spanier, Jonathan E; Grinberg, Ilya; West, Don Vincent


    Disclosed herein are ferroelectric perovskites characterized as having a band gap, Egap, of less than 2.5 eV. Also disclosed are compounds comprising a solid solution of KNbO3 and BaNi1/2Nb1/2O3-delta, wherein delta is in the range of from 0 to about 1. The specification also discloses photovoltaic devices comprising one or more solar absorbing layers, wherein at least one of the solar absorbing layers comprises a semiconducting ferroelectric layer. Finally, this patent application provides solar cell, comprising: a heterojunction of n- and p-type semiconductors characterized as comprising an interface layer disposed between the n- and p-type semiconductors, the interface layer comprising a semiconducting ferroelectric absorber layer capable of enhancing light absorption and carrier separation.

  11. Influence of phonons on semiconductor quantum emission

    Feldtmann, Thomas


    A microscopic theory of interacting charge carriers, lattice vibrations, and light modes in semiconductor systems is presented. The theory is applied to study quantum dots and phonon-assisted luminescence in bulk semiconductors and heterostructures. (orig.)

  12. Fundamentals of semiconductors physics and materials properties

    Yu, Peter Y


    Provides detailed explanations of the electronic, vibrational, transport, and optical properties of semiconductors. This textbook emphasizes understanding the physical properties of Si and similar tetrahedrally coordinated semiconductors and features an extensive collection of tables of material parameters, figures, and problems.

  13. Semiconductor structure and recess formation etch technique

    Lu, Bin; Sun, Min; Palacios, Tomas Apostol


    A semiconductor structure has a first layer that includes a first semiconductor material and a second layer that includes a second semiconductor material. The first semiconductor material is selectively etchable over the second semiconductor material using a first etching process. The first layer is disposed over the second layer. A recess is disposed at least in the first layer. Also described is a method of forming a semiconductor structure that includes a recess. The method includes etching a region in a first layer using a first etching process. The first layer includes a first semiconductor material. The first etching process stops at a second layer beneath the first layer. The second layer includes a second semiconductor material.

  14. Encapsulation of indomethacin using coaxial ultrasonic atomization followed by solvent evaporation.

    Graves, Richard A; Poole, Daniel; Moiseyev, Raisa; Bostanian, Levon A; Mandal, Tarun K


    We have encapsulated indomethacin into poly (lactide-co-glycolide) (PLGA) using coaxial ultrasonic atomization technique. The specific aims of this study were to evaluate the effect of drug loading and a change in relative concentration of polymer in the inner and outer layers of coflowing spray liquids on the physicochemical characteristics of the particles. Indomethacin, a non steroidal anti-inflammatory drug, was selected as a model compound. The micro/nanocapsules prepared using a drug free PLGA solution as an outer layer showed higher encapsulation efficiency. Thermal analysis of the formulations indicated that indomethacin was dissolved within the PLGA matrix. The formulations prepared with 25 mg indomethacin showed relatively smaller particle size compared with the formulations prepared with 50 mg indomethacin. The particles, in general, showed bi- and tri-modal distribution. Irrespective of the compositions of the liquids 1 and 2, all the particles were smooth and spherical. A cross-section view of the particles revealed the presence of three different internal morphologies. These formulations were a mixture of hollow or solid spheres, and single or multiple spheres encapsulated into a larger sphere. To the best of our knowledge, this is the first study revealing the cross-sectional view of particles prepared with coaxial ultrasonic atomization technique.

  15. Advanced characterisation of encapsulated lipid powders regarding microstructure by time domain-nuclear magnetic resonance.

    Linke, Annika; Anzmann, Theresa; Weiss, Jochen; Kohlus, Reinhard


    Encapsulation is an established technique to protect sensitive materials from environmental stress. In order to understand the physical protection mechanism against oxidation, knowledge about the powder microstructure is required. Time domain-nuclear magnetic resonance (TD-NMR) has the potential to determine the surface oil (SO) and droplet size distribution by relaxation and restricted self-diffusion, respectively. The amount of SO, the retention and encapsulation efficiency are determined based on a lipid balance. The oil load of the initial powder and after SO removal is measured by TD-NMR. The results correlate with gravimetric and photometric references. The oil droplet size obtained by TD-NMR correlates well with static light scattering. The diameter of droplets in emulsions and dried powder both measured by TD-NMR, correlates (r = 0.998), implying that oil droplets embedded in a solid matrix can be measured. Summarising, TD-NMR allows analysis of the microstructure of encapsulated lipid powders, in a rapid, simple and non-destructive way.

  16. Encapsulation of poorly water-soluble drugs into organic nanotubes for improving drug dissolution.

    Moribe, Kunikazu; Makishima, Takashi; Higashi, Kenjirou; Liu, Nan; Limwikrant, Waree; Ding, Wuxiao; Masuda, Mitsutoshi; Shimizu, Toshimi; Yamamoto, Keiji


    Hydrocortisone (HC), a poorly water-soluble drug, was encapsulated within organic nanotubes (ONTs), which were formed via the self-assembly of N-{12-[(2-α,β-d-glucopyranosyl) carbamoyl]dodecanyl}-glycylglycylglycine acid. The stability of the ONTs was evaluated in ten organic solvents, of differing polarities, by field emission transmission electron microscopy. The ONTs maintained their stable tubular structure in the highly polar solvents, such as ethanol and acetone. Furthermore, solution-state (1)H-NMR spectroscopy confirmed that they were practically insoluble in acetone at 25°C (0.015 mg/mL). HC-loaded ONTs were prepared by solvent evaporation using acetone. A sample with a 3/7 weight ratio of HC/ONT was analyzed by powder X-ray diffraction, which confirmed the presence of a halo pattern and the absence of any crystalline HC peak. HC peak broadening, observed by solid-state (13)C-NMR measurements of the evaporated sample, indicated the absence of HC crystals. These results indicated that HC was successfully encapsulated in ONT as an amorphous state. Improvements of the HC dissolution rate were clearly observed in aqueous media at both pH 1.2 and 6.8, probably due to HC amorphization in the ONTs. Phenytoin, another poorly water-soluble drug, also showed significant dissolution improvement upon ONT encapsulation. Therefore, ONTs can serve as an alternative pharmaceutical excipient to enhance the bioavailability of poorly water-soluble drugs.

  17. Use of a passive equilibration methodology to encapsulate cisplatin into preformed thermosensitive liposomes.

    Woo, Janet; Chiu, Gigi N C; Karlsson, Göran; Wasan, Ellen; Ickenstein, Ludger; Edwards, Katarina; Bally, Marcel B


    A conventional, cholesterol-containing liposome formulation of cisplatin has demonstrated insignificant activity in clinical trials, due in part, to insufficient release of encapsulated content following localization within solid tumors. For this reason, the development of a triggered release liposome formulation is desirable. In this report, cisplatin was encapsulated into lysolipid-containing thermosensitive liposomes (LTSL) using a novel technique, which relies on the equilibration of cisplatin across the liposomal membrane at temperatures above the gel-to-liquid crystalline phase transition temperature (TC) of the bulk phospholipid. Mild heating and drug loading into LTSL did not induce morphological changes of the liposomes. In vitro data demonstrated that >95% of encapsulated cisplatin was released from LTSL within 5 min following mild heating at 42 degrees C, while liposomes exhibited 70% release of cisplatin at 42 degrees C, and cholesterol-containing liposomes exhibited negligible drug release at 42 degrees C. The pharmacokinetic profiles of LTSL- and TSL-cisplatin indicated that these formulations were rapidly eliminated from circulation (terminal t(1/2) of 1.09 and 2.83 h, respectively). The therapeutic utility of LTSL-cisplatin formulation will be based on strategies where hyperthermia is applied prior to the administration of the liposomal drug-a strategy similar to that used in the clinical assessment of LTSL-doxorubicin formulation.

  18. A Study of the Environmental Performance on Hazardous Waste Management of the Semiconductor and Electronics Industries in Selected Industrial Estates in Luzon, Philippines

    Genandrialine L. Peralta


    In the Philippines, the semiconductor and electronic industry contributes about 70% of export earnings. More than half of the companies inside industrial estates in the country are semiconductor and electronic firms. These firms are among the major contributors of hazardous wastes released through different media, notably solid and semi-solid wastes. The environmental performance indicator, amount of hazardous waste generated per employee, was selected in this study since it is the main envir...

  19. Model of coherent transport in metal-insulator-midband gap semiconductor-insulator-semiconductor structure

    Abramov, I. I.; Danilyuk, A. L.


    A kinetic model of coherent transport with self-organized carrier transfer via midband gap semiconductor states in metal-insulator-midband gap semiconductor-insulator-semiconductor structure at room temperature is proposed. The coherent transport at room temperature can be a result of continuous oscillations of charge carriers at midband gap semiconductor states.

  20. Ultrafast THz Saturable Absorption in Doped Semiconductors

    Turchinovich, Dmitry; Hoffmann, Matthias C.


    We demonstrate ultrafast THz saturable absorption in n-doped semiconductors by nonlinear THz time-domain spectroscopy. This effect is caused by the semiconductor conductivity modulation due to electron heating and satellite-valley scattering in strong THz fields.......We demonstrate ultrafast THz saturable absorption in n-doped semiconductors by nonlinear THz time-domain spectroscopy. This effect is caused by the semiconductor conductivity modulation due to electron heating and satellite-valley scattering in strong THz fields....

  1. Semiconductor devices having a recessed electrode structure

    Palacios, Tomas Apostol; Lu, Bin; Matioli, Elison de Nazareth


    An electrode structure is described in which conductive regions are recessed into a semiconductor region. Trenches may be formed in a semiconductor region, such that conductive regions can be formed in the trenches. The electrode structure may be used in semiconductor devices such as field effect transistors or diodes. Nitride-based power semiconductor devices are described including such an electrode structure, which can reduce leakage current and otherwise improve performance.

  2. Semiconductor assisted metal deposition for nanolithography applications

    Rajh, Tijana; Meshkov, Natalia; Nedelijkovic, Jovan M.; Skubal, Laura R.; Tiede, David M.; Thurnauer, Marion


    An article of manufacture and method of forming nanoparticle sized material components. A semiconductor oxide substrate includes nanoparticles of semiconductor oxide. A modifier is deposited onto the nanoparticles, and a source of metal ions are deposited in association with the semiconductor and the modifier, the modifier enabling electronic hole scavenging and chelation of the metal ions. The metal ions and modifier are illuminated to cause reduction of the metal ions to metal onto the semiconductor nanoparticles.

  3. Semiconductor electrode with improved photostability characteristics

    Frank, Arthur J.


    An electrode is disclosed for use in photoelectrochemical cells having an electrolyte which includes an aqueous constituent. The electrode includes a semiconductor and a hydrophobic film disposed between the semiconductor and the aqueous constituent. The hydrophobic film is adapted to permit charges to pass therethrough while substantially decreasing the activity of the aqueous constituent at the semiconductor surface thereby decreasing the photodegradation of the semiconductor electrode.

  4. Semiconductor nanocrystal-based phagokinetic tracking

    Alivisatos, A Paul; Larabell, Carolyn A; Parak, Wolfgang J; Le Gros, Mark; Boudreau, Rosanne


    Methods for determining metabolic properties of living cells through the uptake of semiconductor nanocrystals by cells. Generally the methods require a layer of neutral or hydrophilic semiconductor nanocrystals and a layer of cells seeded onto a culture surface and changes in the layer of semiconductor nanocrystals are detected. The observed changes made to the layer of semiconductor nanocrystals can be correlated to such metabolic properties as metastatic potential, cell motility or migration.

  5. Diode having trenches in a semiconductor region

    Palacios, Tomas Apostol; Lu, Bin; Matioli, Elison de Nazareth


    An electrode structure is described in which conductive regions are recessed into a semiconductor region. Trenches may be formed in a semiconductor region, such that conductive regions can be formed in the trenches. The electrode structure may be used in semiconductor devices such as field effect transistors or diodes. Nitride-based power semiconductor devices are described including such an electrode structure, which can reduce leakage current and otherwise improve performance.

  6. Quantitative evaluation of chemisorption processes on semiconductors

    Rothschild, A.; Komem, Y.; Ashkenasy, N.


    This article presents a method for numerical computation of the degree of coverage of chemisorbates and the resultant surface band bending as a function of the ambient gas pressure, temperature, and semiconductor doping level. This method enables quantitative evaluation of the effect of chemisorption on the electronic properties of semiconductor surfaces, such as the work function and surface conductivity, which is of great importance for many applications such as solid- state chemical sensors and electro-optical devices. The method is applied for simulating the chemisorption behavior of oxygen on n-type CdS, a process that has been investigated extensively due to its impact on the photoconductive properties of CdS photodetectors. The simulation demonstrates that the chemisorption of adions saturates when the Fermi level becomes aligned with the chemisorption-induced surface states, limiting their coverage to a small fraction of a monolayer. The degree of coverage of chemisorbed adions is proportional to the square root of the doping level, while neutral adsorbates are independent of the doping level. It is shown that the chemisorption of neutral adsorbates behaves according to the well-known Langmuir model, regardless of the existence of charged species on the surface, while charged adions do not obey Langmuir's isotherm. In addition, it is found that in depletive chemisorption processes the resultant surface band bending increases by 2.3kT (where k is the Boltzmann constant and T is the temperature) when the gas pressure increases by one order of magnitude or when the doping level increases by two orders of magnitude.

  7. Stabilization of reactive species by supramolecular encapsulation.

    Galan, Albano; Ballester, Pablo


    Molecular containers have attracted the interest of supramolecular chemists since the early beginnings of the field. Cavitands' inner cavities were quickly exploited by Cram and Warmuth to construct covalent containers able to stabilize and assist the characterization of short-lived reactive species such as cyclobutadiene or o-benzyne. Since then, more complex molecular architectures have been prepared able to store and isolate a myriad of fleeting species (i.e. organometallic compounds, cationic species, radical initiators…). In this review we cover selected examples of the stabilization of reactive species by encapsulation in molecular containers from the first reports of covalent containers described by Cram et al. to the most recent examples of containers with self-assembled structure (metal coordination cages and hydrogen bonded capsules). Finally, we briefly review examples reported by Rebek et al. in which elusive reaction intermediates could be detected in the inner cavities of self-folding resorcin[4]arene cavitands by the formation of covalent host-guest complexes. The utilization of encapsulated reactive species in catalysis or synthesis is not covered.

  8. FBG sensor of breathing encapsulated into polydimethylsiloxane

    Fajkus, Marcel; Nedoma, Jan; Siska, Petr; Vasinek, Vladimir


    The technology of Fiber Bragg grating (FBG) belongs to the most widespread fiber-optic sensors. They are used for measuring a large number of physical and chemical quantities. Small size, immunity to electromagnetic interference, high sensitivity and a principle of information encoding about the measurement value into spectral characteristics causes usability of FBG sensors in medicine for monitoring vital signs such as temperature, blood pressure, pulse, and respiration. An important factor is the use of an inert material for the encapsulation of Bragg gratings in this area. A suitable choice is a polydimethylsiloxane (PDMS) elastomer having excellent thermal and elastic properties. Experimental results describe the creation of FBG sensory prototype for monitoring breathing in this paper. The sensor is realized by encapsulation of Bragg grating into PDMS. The FBG sensor is mounted on the elastic contact strap which encircles the chest of the patient. This tension leads to a spectral shift of the reflected light from the FBG. For measurement, we used a broadband light source Light-Emitting Diode (LED) with central wavelength 1550 nm and optical spectrum analyzer.

  9. Accelerated degradation studies of encapsulation polymers

    Weiss, Karl-Anders; Huelsmann, Jan Philip; Kaltenbach, Thomas; Philipp, Daniel; Schuhmacher, Tanja; Wirth, Jochen; Koehl, Michael


    The estimation of PV-modules lifetime facilitates the further development and helps to lower risks for producers and investors. One base for this extensive testing and simulation work is the knowledge of the chemical degradation processes and their kinetics, as well as of the permeation of water and oxygen into the module, especially of the encapsulant. Besides ethylen-vinylacetate copolymer (EVA), which is the dominant material for encapsulation, new materials become available and need the assessment of their properties and the durability impact. Accelerated durability tests were performed on different EVA materials. The paper reports on several measurement methods for analysis of the polymers that were used, FT-IR with attenuated total reflection (ATR), and Raman microscopy, e.g. It is very important to identify degradation products and intermediates in order to identify the leading degradation processes and their kinetics as well as potential interactions between different processes. Another important factor for the degradation of the PV-modules and the concerned polymers in particular is the permeation of reactive substances, especially of water vapor, into and inside the modules. The paper shows results of permeation measurements of the new materials, as well as FEM-based numerical simulations of the humidity diffusion within a PV-module what is an important step towards the calculation of the chemical degradation using numerical simulation tools in the future.

  10. Idiopathic sclerosing encapsulating peritonitis (or abdominal cocoon

    Legakis Nikolaos


    Full Text Available Abstract Background Idiopathic sclerosing encapsulating peritonitis (or abdominal cocoon is a rare cause of small bowel obstruction, especially in adult population. Diagnosis is usually incidental at laparotomy. We discuss one such rare case, outlining the fact that an intra-operative surprise diagnosis could have been facilitated by previous investigations. Case presentation A 56 year-old man presented in A&E department with small bowel ileus. He had a history of 6 similar episodes of small bowel obstruction in the past 4 years, which resolved with conservative treatment. Pre-operative work-up did not reveal any specific etiology. At laparotomy, a fibrous capsule was revealed, in which small bowel loops were encased, with the presence of interloop adhesions. A diagnosis of abdominal cocoon was established and extensive adhesiolysis was performed. The patient had an uneventful recovery and follow-up. Conclusion Idiopathic sclerosing encapsulating peritonitis, although rare, may be the cause of a common surgical emergency such as small bowel ileus, especially in cases with attacks of non-strangulating obstruction in the same individual. A high index of clinical suspicion may be generated by the recurrent character of small bowel ileus combined with relevant imaging findings and lack of other plausible etiologies. Clinicians must rigorously pursue a preoperative diagnosis, as it may prevent a "surprise" upon laparotomy and result in proper management.

  11. Semiconductor films on flexible iridium substrates

    Goyal, Amit


    A laminate semiconductor article includes a flexible substrate, an optional biaxially textured oxide buffer system on the flexible substrate, a biaxially textured Ir-based buffer layer on the substrate or the buffer system, and an epitaxial layer of a semiconductor. Ir can serve as a substrate with an epitaxial layer of a semiconductor thereon.

  12. Microencapsulation of Lactobacillus acidophilus La-5 by spray-drying using sweet whey and skim milk as encapsulating materials.

    Maciel, G M; Chaves, K S; Grosso, C R F; Gigante, M L


    The aim of this study was to evaluate the effect of encapsulating material on encapsulation yield, resistance to passage through simulated gastrointestinal conditions, and viability of Lactobacillus acidophilus La-5 during storage. Microparticles were produced from reconstituted sweet whey or skim milk (30% total solids) inoculated with a suspension of L. acidophilus La-5 (1% vol/vol) and subjected to spray-drying at inlet and outlet temperatures of 180°C and 85 to 95°C, respectively. The samples were packed, vacuum-sealed, and stored at 4°C and 25°C. Encapsulation yield, moisture content, and resistance of microencapsulated L. acidophilus La-5 compared with free cells (control) during exposure to in vitro gastrointestinal conditions (pH 2.0 and 7.0) were evaluated. Viability was assessed after 0, 7, 15, 30, 45, 60, and 90d of storage. The experiments were repeated 3 times and data were analyzed by ANOVA and Tukey test for the comparison between means. The encapsulating material did not significantly affect encapsulation yield, average diameter, or moisture of the particles, which averaged 76.58±4.72%, 12.94±0.78μm, and 4.53±0.32%, respectively. Both microparticle types were effective in protecting the probiotic during gastrointestinal simulation, and the skim milk microparticles favored an increase in viability of L. acidophilus La-5. Regardless of the encapsulating material and temperature of storage, viability of the microencapsulated L. acidophilus La-5 decreased on average 0.43 log cfu/g at the end of 90d of storage, remaining higher than 10(6)cfu/g. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  13. Progress Made in the Studies of Novel Materials for Organic Semiconductors


    @@ Co-funded by NSFC, Ministry of Science & Technology of China (MOST) and the Chinese Academy of Sciences (CAS), researchers at the Key Laboratory of Organic Solids, ICCAS, made progress in designing and synthesis of n- and p-type organic semiconductors.

  14. Towards filament free semiconductor lasers

    McInerney, John; O'Brien, Peter; Skovgaard, Peter M. W.


    We outline physical models and simulations for suppression of self-focusing and filamentation in large aperture semiconductor lasers. The principal technical objective is to generate multi-watt CW or quasi-CW outputs with nearly diffraction limited beams, suitable for long distance free space...... propagation structures in lasers and amplifiers which suppress lateral reflections....

  15. 2010 Defects in Semiconductors GRC

    Shengbai Zhang


    Continuing its tradition of excellence, this Gordon Conference will focus on research at the forefront of the field of defects in semiconductors. The conference will have a strong emphasis on the control of defects during growth and processing, as well as an emphasis on the development of novel defect detection methods and first-principles defect theories. Electronic, magnetic, and optical properties of bulk, thin film, and nanoscale semiconductors will be discussed in detail. In contrast to many conferences, which tend to focus on specific semiconductors, this conference will deal with point and extended defects in a broad range of electronic materials. This approach has proved to be extremely fruitful for advancing fundamental understanding in emerging materials such as wide-band-gap semiconductors, oxides, sp{sup 2} carbon based-materials, and photovoltaic/solar cell materials, and in understanding important defect phenomena such as doping bottleneck in nanostructures and the diffusion of defects and impurities. The program consists of about twenty invited talks and a number of contributed poster sessions. The emphasis should be on work which has yet to be published. The large amount of discussion time provides an ideal forum for dealing with topics that are new and/or controversial.

  16. Ultrafast Spectroscopy of Semiconductor Devices

    Borri, Paola; Langbein, Wolfgang; Hvam, Jørn Marcher


    In this work we present an experimental technique for investigating ultrafast carrier dynamics in semiconductor optical amplifiers at room temperature. These dynamics, influenced by carrier heating, spectral hole-burning and two-photon absorption, are very important for device applications...

  17. Terahertz Nonlinear Optics in Semiconductors

    Turchinovich, Dmitry; Hvam, Jørn Märcher; Hoffmann, Matthias C.


    We demonstrate the nonlinear optical effects – selfphase modulation and saturable absorption of a single-cycle THz pulse in a semiconductor. Resulting from THz-induced modulation of Drude plasma, these nonlinear optical effects, in particular, lead to self-shortening and nonlinear spectral...

  18. Electron beam pumped semiconductor laser

    Hug, William F. (Inventor); Reid, Ray D. (Inventor)


    Electron-beam-pumped semiconductor ultra-violet optical sources (ESUVOSs) are disclosed that use ballistic electron pumped wide bandgap semiconductor materials. The sources may produce incoherent radiation and take the form of electron-beam-pumped light emitting triodes (ELETs). The sources may produce coherent radiation and take the form of electron-beam-pumped laser triodes (ELTs). The ELTs may take the form of electron-beam-pumped vertical cavity surface emitting lasers (EVCSEL) or edge emitting electron-beam-pumped lasers (EEELs). The semiconductor medium may take the form of an aluminum gallium nitride alloy that has a mole fraction of aluminum selected to give a desired emission wavelength, diamond, or diamond-like carbon (DLC). The sources may be produced from discrete components that are assembled after their individual formation or they may be produced using batch MEMS-type or semiconductor-type processing techniques to build them up in a whole or partial monolithic manner, or combination thereof.

  19. Semiconductor technology program: Progress briefs

    Galloway, K. F.; Scace, R. I.; Walters, E. J.


    Measurement technology for semiconductor materials, process control, and devices, is discussed. Silicon and silicon based devices are emphasized. Highlighted activities include semiinsulating GaAs characterization, an automatic scanning spectroscopic ellipsometer, linewidth measurement and coherence, bandgap narrowing effects in silicon, the evaluation of electrical linewidth uniformity, and arsenicomplanted profiles in silicon.

  20. Energy transfer with semiconductor nanocrystals

    Rogach, A.L.; Klar, T.A.; Lupton, J.M.; Meijerink, A.; Feldmann, J.


    Fo¨ rster (or fluorescence) resonant energy transfer (FRET) is a powerful spectroscopic technique to study interactions, conformational and distance changes, in hybrid nanosystems. Semiconductor nanocrystals, also known as colloidal quantum dots, are highly efficient fluorophores with a strong band-

  1. Atomistic Models of Amorphous Semiconductors

    Jarolimek, K.


    Crystalline silicon is probably the best studied material, widely used by the semiconductor industry. The subject of this thesis is an intriguing form of this element namely amorphous silicon. It can contain a varying amount of hydrogen and is denoted as a-Si:H. It completely lacks the neat long

  2. A variable frequency semiconductor laser

    Tosikhiro, F.; Khiromoto, S.


    A variable frequency, power stabilized semiconductor laser is patented. This laser includes, in addition to an active layer, a photoconducting channel layer and a layer made from a material manifesting a Pockels effect. A voltage is injected between these two layers to vary the emission frequency. The laser pumping voltage is stabilized.

  3. Quantification of encapsulated bioburden in spacecraft polymer materials by cultivation-dependent and molecular methods.

    Anja Bauermeister

    Full Text Available Bioburden encapsulated in spacecraft polymers (such as adhesives and coatings poses a potential risk to jeopardize scientific exploration of other celestial bodies. This is particularly critical for spacecraft components intended for hard landing. So far, it remained unclear if polymers are indeed a source of microbial contamination. In addition, data with respect to survival of microbes during the embedding/polymerization process are sparse. In this study we developed testing strategies to quantitatively examine encapsulated bioburden in five different polymers used frequently and in large quantities on spaceflight hardware. As quantitative extraction of the bioburden from polymerized (solid materials did not prove feasible, contaminants were extracted from uncured precursors. Cultivation-based analyses revealed <0.1-2.5 colony forming units (cfu per cm3 polymer, whereas quantitative PCR-based detection of contaminants indicated considerably higher values, despite low DNA extraction efficiency. Results obtained from this approach reflect the most conservative proxy for encapsulated bioburden, as they give the maximum bioburden of the polymers irrespective of any additional physical and chemical stress occurring during polymerization. To address the latter issue, we deployed an embedding model to elucidate and monitor the physiological status of embedded Bacillus safensis spores in a cured polymer. Staining approaches using AlexaFluor succinimidyl ester 488 (AF488, propidium monoazide (PMA, CTC (5-cyano-2,3-diotolyl tetrazolium chloride demonstrated that embedded spores retained integrity, germination and cultivation ability even after polymerization of the adhesive Scotch-Weld 2216 B/A. Using the methods presented here, we were able to estimate the worst case contribution of encapsulated bioburden in different polymers to the bioburden of spacecraft. We demonstrated that spores were not affected by polymerization processes. Besides Planetary

  4. Hexameric Capsules Studied by Magic Angle Spinning Solid-State NMR Spectroscopy: Identifying Solvent Molecules in Pyrogallol[4]arene Capsules.

    Avram, Liat; Goldbourt, Amir; Cohen, Yoram


    Powders of pyrogallol[4]arene hexamers were produced by evaporation from organic solvents and were studied, for the first time, by magic angle spinning solid-state NMR (MAS ssNMR). Evaporation selectively removed non-encapsulated solvent molecules leaving stable hexameric capsules encapsulating solvent molecules. After exposure of the powder to solvent vapors, (1)H/(13)C heteronuclear correlation MAS ssNMR experiments were used to assign the signals of the external and encapsulated solvent molecules. The formed capsules were stable for months and the process of solvent encapsulation was reversible. According to the ssNMR experiments, the encapsulated solvent molecules occupy different sites and those sites differ in their mobility. The presented approach paves the way for studying guest exchange, guest affinity, and gas storage in hexamers of this type in the solid state.

  5. Solid-State Laser Engineering

    Koechner, Walter


    Written from an industrial perspective, Solid-State Laser Engineering discusses in detail the characteristics, design, construction, and performance of solid-state lasers. Emphasis is placed on engineering and practical considerations; phenomenological aspects using models are preferred to abstract mathematical derivations. Since its first edition almost 30 years ago this book has become the standard in the field of solid-state lasers for scientists,engineers and graduate students. This new edition has been extensively revised and updated to account for recent developments in the areas of diode-laser pumping, laser materials and nonlinear crystals. Completely new sections have been added dealing with frequency control, the theory of mode-locking, femto second lasers, high efficiency harmonic generation, passive and acousto-optic Q-switching, semiconductor saturable absorber mirrors (SESAM) and peridically poled nonlinear crystals.

  6. Light Scattering in Solid IX

    Cardona, Manuel


    This is the ninth volume of a well-established series in which expert practitioners discuss topical aspects of light scattering in solids. It reviews recent developments concerning mainly semiconductor nanostructures and inelastic x-ray scattering, including both coherent time-domain and spontaneous scattering studies. In the past few years, light scattering has become one of the most important research and characterization methods for studying carbon nanotubes and semiconducting quantum dots, and a crucial tool for exploring the coupled exciton--photon system in semiconductor cavities. Among the novel techniques discussed in this volume are pump--probe ultrafast measurements and those which use synchrotron radiation as light source. The book addresses improvements in the intensity, beam quality and time synchronization of modern synchrotron sources, which made it possible to measure the phonon dispersion in very small samples and to determine electronic energy bands as well as enabling real-time observations...

  7. Encapsulation of essential oils in zein nanosperical particles

    Essential oils, oregano, red thyme, and cassia (100% pure oil), were encapsulated by phase separation into zein particles. Typical yields were between 65% and 75% of product. Encapsulation efficiency of all oils was 87% except for cassia oil which was 49%. Loading efficiency of all oils was 22% exce...

  8. Characterization studies of lower and non-TDI polyurethane encapsulants

    Wilson, M.H.


    Polyurethane prepolymers containing toluene diisocyanate (TDI) are used within the Nuclear Weapons complex for many adhesive and encapsulation applications. As part of a program for minimizing hazards to workers and the environment, TDI will be eliminated. This report presents evaluation of alternative encapsulants.

  9. Photovoltaic-module encapsulation design and materials selection: Volume 1

    Cuddihy, E.; Carroll, W.; Coulbert, C.; Gupta, A.; Liang, R.


    Encapsulation-material system requirements, material-selection criteria, and the status and properties of encapsulation materials and processes available to the module manufacturer are presented in detail. Technical and economic goals established for photovoltaic modules and encapsulation systems and their status are described for material suppliers to assist them in assessing the suitability of materials in their product lines and the potential of new-material products. A comprehensive discussion of available encapsulation technology and data is presented to facilitate design and material selection for silicon flat-plate photovoltaic modules, using the best materials available and processes optimized for specific power applications and geographic sites. A basis is provided for specifying the operational and environmental loads that encapsulation material systems must resist. Potential deployment sites for which cost effectiveness may be achieved at a module price much greater than $0.70/W/sub p/, are also considered; data on higher-cost encapsulant materials and processes that may be in use and other material candidates that may be justified for special application are discussed. Described are encapsulation-system functional requirements and candidate design concepts and materials that have been identified and analyzed as having the best potential to meet the cost and performance goals for the Flat-Plate Solar Array Project. The available data on encapsulant material properties, fabrication processing, and module life and durability characteristics are presented.

  10. Encapsulation of energetic materials by cooling and electrospray crystallization

    Reus, M.A.; Horst, J.H. ter; Stankiewicz, A.I.; Heijden, A.E.D.M. van der


    In this work cooling and electrospray crystallization have been used to create encapsulated (sub-)micron sized particles of different crystalline materials. Encapsulation experiments have been conducted, creating the core particle in situ from solution, with the model systems isonicotinamide (INA) –

  11. Encapsulation of energetic materials by cooling and electrospray crystallization

    Reus, M.A.; Horst, J.H. ter; Stankiewicz, A.I.; Heijden, A.E.D.M. van der


    In this work cooling and electrospray crystallization have been used to create encapsulated (sub-)micron sized particles of different crystalline materials. Encapsulation experiments have been conducted, creating the core particle in situ from solution, with the model systems isonicotinamide (INA) –

  12. The interpretation of encapsulating anaphors in Spanish and their functions

    Dam, Lotte


    Encapsulating anaphors differ from other types of anaphor by having one or more situations - not an entity - as its referent. The main aim of the article is to propose a hypothesis for how anaphoric encapsulation is resolved. The hypothesis builds on the cognitive linguistic theory of instruction...

  13. Advanced Semiconductor Devices

    Shur, Michael S.; Maki, Paul A.; Kolodzey, James


    I. Wide band gap devices. Wide-Bandgap Semiconductor devices for automotive applications / M. Sugimoto ... [et al.]. A GaN on SiC HFET device technology for wireless infrastructure applications / B. Green ... [et al.]. Drift velocity limitation in GaN HEMT channels / A. Matulionis. Simulations of field-plated and recessed gate gallium nitride-based heterojunction field-effect transistors / V. O. Turin, M. S. Shur and D. B. Veksler. Low temperature electroluminescence of green and deep green GaInN/GaN light emitting diodes / Y. Li ... [et al.]. Spatial spectral analysis in high brightness GaInN/GaN light emitting diodes / T. Detchprohm ... [et al.]. Self-induced surface texturing of Al2O3 by means of inductively coupled plasma reactive ion etching in Cl2 chemistry / P. Batoni ... [et al.]. Field and termionic field transport in aluminium gallium arsenide heterojunction barriers / D. V. Morgan and A. Porch. Electrical characteristics and carrier lifetime measurements in high voltage 4H-SiC PiN diodes / P. A. Losee ... [et al.]. Geometry and short channel effects on enhancement-mode n-Channel GaN MOSFETs on p and n- GaN/sapphire substrates / W. Huang, T. Khan and T. P. Chow. 4H-SiC Vertical RESURF Schottky Rectifiers and MOSFETs / Y. Wang, P. A. Losee and T. P. Chow. Present status and future Directions of SiGe HBT technology / M. H. Khater ... [et al.]Optical properties of GaInN/GaN multi-quantum Wells structure and light emitting diode grown by metalorganic chemical vapor phase epitaxy / J. Senawiratne ... [et al.]. Electrical comparison of Ta/Ti/Al/Mo/Au and Ti/Al/Mo/Au Ohmic contacts on undoped GaN HEMTs structure with AlN interlayer / Y. Sun and L. F. Eastman. Above 2 A/mm drain current density of GaN HEMTs grown on sapphire / F. Medjdoub ... [et al.]. Focused thermal beam direct patterning on InGaN during molecular beam epitaxy / X. Chen, W. J. Schaff and L. F. Eastman -- II. Terahertz and millimeter wave devices. Temperature-dependent microwave performance of

  14. Solid propellants.

    Marsh, H. E., Jr.; Hutchison, J. J.


    The basic principles underlying propulsion by rocket motor are examined together with the configuration of a solid propellant motor. Solid propellants and their preparation are discussed, giving attention to homogeneous propellants, composite propellants, energetic considerations in choosing a solid propellant, the processing of composite propellants, and some examples of new developments. The performance of solid propellants is investigated, taking into account characteristics velocity, the specific impulse, and performance calculations. Aspects of propellant development considered include nonperformance requirements for solid propellants, the approach to development, propellant mechanical properties, and future trends.

  15. Tracking Hypoxic Signaling in Encapsulated Stem Cells

    Sahai, Suchit; McFarland, Rachel; Skiles, Mathew L.; Sullivan, Denise; Williams, Amanda


    Oxygen is not only a nutrient but also an important signaling molecule whose concentration can influence the fate of stem cells. This study details the development of a marker of hypoxic signaling for use with encapsulated cells. Testing of the marker was performed with adipose-derived stem cells (ADSCs) in two-dimensional (2D) and 3D culture conditions in varied oxygen environments. The cells were genetically modified with our hypoxia marker, which produces a red fluorescent protein (DsRed-DR), under the control of a hypoxia-responsive element (HRE) trimer. For 3D culture, ADSCs were encapsulated in poly(ethylene glycol)–based hydrogels. The hypoxia marker (termed HRE DsRed-DR) is built on a recombinant adenovirus and ADSCs infected with the marker will display red fluorescence when hypoxic signaling is active. This marker was not designed to measure local oxygen concentration but rather to show how a cell perceives its local oxygen concentration. ADSCs cultured in both 2D and 3D were exposed to 20% or 1% oxygen environments for 96 h. In 2D at 20% O2, the marker signal was not observed during the study period. In 1% O2, the fluorescent signal was first observed at 24 h, with maximum prevalence observed at 96 h as 59%±3% cells expressed the marker. In 3D, the signal was observed in both 1% and 20% O2. The onset of signal in 1% O2 was observed at 4 h, reaching maximum prevalence at 96 h with 76%±4% cells expressing the marker. Interestingly, hypoxic signal was also observed in 20% O2, with 13%±3% cells showing positive marker signal after 96 h. The transcription factor subunit hypoxia inducible factor-1α was tracked in these cells over the same time period by immunostaining and western blot analysis. Immunostaining results in 2D correlated well with our marker at 72 h and 96 h, but 3D results did not correlate well. The western blotting results in 2D and 3D correlated well with the fluorescent marker. The HRE DsRed-DR virus can be used to track

  16. Primary Amyloidosis Presenting as Small Bowel Encapsulation

    Jennifer Jones


    Full Text Available Amyloidosis is a pathological process which encompasses a spectrum of diseases that result from extracellular deposition of pathological fibrillar proteins. Clinical presentations vary depending on the organs involved. There is no documented case of amyloidosis presenting as small bowel encapsulation. A previously healthy 62-year-old man developed a small bowel obstruction in 1997. At surgery, a peculiar membrane encasing his entire small bowel was discovered. This appeared to have no vascularity and was removed without difficulty, exposing a grossly normal bowel. Histopathology revealed thick bands of collagen overlying the peritoneal surface, which was congo red positive and showed apple green birefringence. The findings were consistent with encapsulating peritonitis due to amyloidosis. There was no history or symptoms of any chronic inflammatory condition and he became symptom-free postoperatively. An abdominal fat pad biopsy failed to demonstrate amyloidosis. Endoscopic duodenal biopsies revealed classical primary amyloidosis. Quantitative immunoglobulins, lactate dehydrogenase, C3, C4 and beta-2 microglobulin were normal. Protein electrophoresis identified monoclonal paraprotein, immunoglobulin G lambda 3.7 g/L. Bone marrow biopsy and aspirate revealed only a mild plasmacytosis (5% to 10%. Echocardiogram and skeletal survey were normal. He had mild proteinuria. Complete blood count, C-reactive protein, calcium, albumin and total protein were normal. No specific therapy was instituted. In January of 1998 the patient remained asymptomatic with no gastrointestinal, cardiovascular or constitutional symptoms. He had developed nephrotic range proteinuria (3.95 g/24 h, microalbuminuria, hypoalbuminemia and a renal biopsy consistent with renal amyloidosis. In 1999 there was an increase in the monoclonal paraprotein (6.2 g/L. The remaining investigations were normal except for an echocardiogram which showed left ventricular hypertrophy but a normal

  17. High-Performance CCSDS Encapsulation Service Implementation in FPGA

    Clare, Loren P.; Torgerson, Jordan L.; Pang, Jackson


    The Consultative Committee for Space Data Systems (CCSDS) Encapsulation Service is a convergence layer between lower-layer space data link framing protocols, such as CCSDS Advanced Orbiting System (AOS), and higher-layer networking protocols, such as CFDP (CCSDS File Delivery Protocol) and Internet Protocol Extension (IPE). CCSDS Encapsulation Service is considered part of the data link layer. The CCSDS AOS implementation is described in the preceding article. Recent advancement in RF modem technology has allowed multi-megabit transmission over space links. With this increase in data rate, the CCSDS Encapsulation Service needs to be optimized to both reduce energy consumption and operate at a high rate. CCSDS Encapsulation Service has been implemented as an intellectual property core so that the aforementioned problems are solved by way of operating the CCSDS Encapsulation Service inside an FPGA. The CCSDS En capsula tion Service in FPGA implementation consists of both packetizing and de-packetizing features

  18. Noncovalent encapsulation of cobaltocenium inside resorcinarene molecular capsules.

    Philip, Ivy; Kaifer, Angel E


    The encapsulation of cobaltocenium (Cob+) inside hexameric molecular capsules of two different resorcinarenes was investigated in dichloromethane solution. Both 1H NMR spectroscopic and voltammetric experiments clearly reveal that Cob+ experiences encapsulation. Diffusion coefficient measurements obtained from PGSE NMR experiments indicate that the molecular capsules exist in dichloromethane solution in the absence of any cations. Bound and free Cob+ ions undergo slow exchange on the NMR time scale, but the bound Cob+ ions rotate and/or tumble freely inside the molecular capsules. Under experimental conditions suitable for voltammetry the encapsulation of Cob+ depends on the nature of the supporting electrolyte. Tetraalkylammonium hexafluorophosphate, tetrafluoroborate, and perchlorate supporting electrolytes prevent the encapsulation of Cob+, while tetraalkylammonium chloride and bromide salts allow it. The nature of the tetraalkylammonium cation plays a smaller role in the encapsulation. Finally, the structure of the resorcinarene also factors into the overall stability of the molecular assembly.

  19. Back-side readout semiconductor photomultiplier

    Choong, Woon-Seng; Holland, Stephen E


    This disclosure provides systems, methods, and apparatus related to semiconductor photomultipliers. In one aspect, a device includes a p-type semiconductor substrate, the p-type semiconductor substrate having a first side and a second side, the first side of the p-type semiconductor substrate defining a recess, and the second side of the p-type semiconductor substrate being doped with n-type ions. A conductive material is disposed in the recess. A p-type epitaxial layer is disposed on the second side of the p-type semiconductor substrate. The p-type epitaxial layer includes a first region proximate the p-type semiconductor substrate, the first region being implanted with p-type ions at a higher doping level than the p-type epitaxial layer, and a second region disposed on the first region, the second region being doped with p-type ions at a higher doping level than the first region.

  20. Theoretical aspects of Microwave Frequency Transport in Generic Dimensionality Semiconductors

    Prati, Enrico


    The present work can be classified as an investigation for the theoretical study of semiconductors in the microwave (?w) frequency domain. This range owns two properties that let it to be a hot subject for the next years: from one side, there is a basic need of such a characterization to get a satisfactory description of the fundamental solid state physics; from the other side there is the urgent need to analyze and increase performances of technological products in order to improve the quali...