bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diameter-dependent morphology of vapour–solid–solid grown ZnSe nanowires
Authors: Zannier V , Grillo V , Rubini S 
Published: September 2014

Abstract
We report on the growth of ZnSe nanowires by molecular beam epitaxy using solid Au nanoparticles as growth seeds. We show that nanowires with diameter below 15 nm are reproducibly straight, while thicker nanowires display a ‘worm-like’ morphology characterized by multiple kinks. This size-dependent morphology does not depend on growth parameters such as substrate temperature, Zn/Se pressure ratio or substrate chemistry, but we believe it is related to the solid state of the metal seed driving the nanowire growth. We finally propose three alternative methods to selectively obtain thin, straight and oriented ZnSe nanowires on GaAs(1 1 1)B.
3C–SiC nanowires luminescence enhancement by coating with a conformal oxides layer
Authors: Fabbri Filippo , Rossi Francesca , Lagonegro Paola , Negri Marco , Ponraj Joice Sophia , Bosi Matteo , Attolini Giovanni , Salviati Giancarlo 
Published: September 2014

Abstract
In this work, we report the light emission properties of different classes of 3C–SiC nanowires. We compare the luminescence of core/shell nanowires where the 3C–SiC core is covered by a SiO
x
shell of different thickness, or coated with different conformal oxide layers (aluminium oxide and gallium oxide), grown by atomic layer deposition. The main result is the enhancement of the 3C–SiC near-band-edge emission at room temperature with the nanowires surface coating, due to carrier's diffusion from the shell to the core, promoted by the alignment between the oxides and SiC bands in a type I quantum-well.
Optical properties of vertical, tilted and in-plane GaN nanowires on different crystallographic orientations of sapphire
Authors: Tessarek C , Figge S , Gust A , Heilmann M , Dieker C , Spiecker E , Christiansen S 
Published: September 2014

Abstract
Self-catalysed and self-organized GaN nanowires were grown on c-, a-, m- and r-plane sapphire by metal-organic vapour phase epitaxy. In dependence on the crystallographic orientation of the sapphire substrate, vertical, tilted and in-plane GaN nanowires were achieved. The nanowire orientation is visualized by scanning electron microscopy and analysed by x-ray diffraction. The influence of the sapphire nitridation step on the nanowire formation is investigated. Spatially and spectrally resolved cathodoluminescence studies are carried out on the GaN nanowires to analyse the influence of the GaN nanowire orientation as well as the presence of both N- and Ga-polar sections in a single nanowire on the optical properties.
Taming excitons in II–VI semiconductor nanowires and nanobelts
Authors: Xu Xinlong , Zhang Qing , Zhang Jun , Zhou Yixuan , Xiong Qihua 
Published: September 2014

Abstract
Excitons are one of the most important fundamental quasi-particles, and are involved in a variety of processes forming the basis of a wide range of opto-electronic and photonic devices based on II–VI semiconductor nanowires and nanobelts, such as light-emitting diodes, photovoltaic cells, photodetectors and nanolasers. A clear understanding of their properties and unveiling the potential engineering for excitons is of particular importance for the design and optimization of nanoscale opto-electronic and photonic devices. Herein, we present a comprehensive review on discussing the fundamental behaviours of the excitons in one-dimensional (1D) II–VI semiconductor nanomaterials (nanowires and nanobelts). We will start with a focus on the unique properties (origin, generation, etc) and dynamics of excitons and exciton complexes in the II–VI semiconductor nanowires and nanobelts. Then we move to the recent progress on the excitonic response in 1D nanomaterials and focus on the tailoring and engineering of excitonic properties through rational controlling of the physical parameters and conditions, intrinsically and extrinsically. These include (1) exciton–exciton interaction, which is important for 1D nanomaterial nanolasing; (2) exciton–phonon interaction, which has interesting applications for laser cooling; and (3) exciton–plasmon interaction, which is the cornerstone towards the realization of plasmonic lasers. The potential of electric field, morphology and size control for excitonic properties is also discussed. Unveiling and controlling excitonic properties in II–VI semiconductor nanowires and nanobelts would promote the development of 1D nanoscience and nanotechnology.
Localization and defects in axial (In,Ga)N/GaN nanowire heterostructures investigated by spatially resolved luminescence spectroscopy
Authors: Lähnemann Jonas , Hauswald Christian , Wölz Martin , Jahn Uwe , Hanke Michael , Geelhaar Lutz , Brandt Oliver 
Published: September 2014

Abstract
(In,Ga)N insertions embedded in self-assembled GaN nanowires (NWs) are of current interest for applications in solid-state light emitters. Such structures exhibit a notoriously broad emission band. We use cathodoluminescence spectral imaging in a scanning electron microscope and micro-photoluminescence spectroscopy on single NWs to learn more about the mechanisms underlying this emission. We observe a shift of the emission energy along the stack of six insertions within single NWs that may be explained by compositional pulling. Our results also corroborate reports that the localization of carriers at potential fluctuations within the insertions plays a crucial role for the luminescence of these NW based emitters. Furthermore, we resolve contributions from both structural and point defects in our measurements.
Polarization features of optically pumped CdS nanowire lasers
Authors: Röder Robert , Ploss Daniel , Kriesch Arian , Buschlinger Robert , Geburt Sebastian , Peschel Ulf , Ronning Carsten 
Published: September 2014

Abstract
High quality CdS nanowires suspended in air were optically pumped both below and above the lasing threshold. The polarization of the pump laser was varied while emission out of the end facet of the nanowire was monitored in a ‘head-on’ measurement geometry. Highest pump-efficiency and most efficient absorption of the pump radiation are demonstrated for an incident electric field being polarized parallel to the nanowire axis. This polarization dependence, which was observed both above the lasing threshold and in the regime of amplified spontaneous emission, is caused by an enhanced absorption for parallel polarized optical pumping. Measured Stokes parameters of the nanowire emission reveal that due to the onset of lasing the degree of polarization rapidly increases from approximately 15 to 85%. Both Stokes parameters and degree of polarization of the nanowire lasing emission are independent of the excitation polarization. The transversal lasing mode is therefore not notably affected by the polarization of the pumping beam, although the supply with optical gain is significantly enhanced for an excitation polarization parallel to the nanowire axis.
Gate modulation of below-band-gap photoconductivity in ZnO nanowire field-effect-transistors
Authors: Cammi Davide , Röder Robert , Ronning Carsten 
Published: September 2014

Abstract
We investigated the modulation of the photoconductivity under below-band gap excitation in single ZnO nanowire field effect transistors. Light excitation at 550 nm does not induce any change in the drain–source current when the gate voltage is kept at V
gs = 0 V, but results in a current increase when it is set to V
gs = −50 V. At this negative value of the gate voltage we further investigated the photo-reaction in the below-band-gap range 400–800 nm, observing a qualitative similar profile for all the photo-current curves. These results were attributed to a local effect, suggesting that the change in conductivity is due to the release of electrons from interface states located between the ZnO nanowire active channel and the gate dielectric SiO2.
Electrostatic spin control in multi-barrier nanowires
Authors: Rossella Francesco , Ercolani Daniele , Sorba Lucia , Beltram Fabio , Roddaro Stefano 
Published: September 2014

Abstract
We demonstrate that a consistent breakdown of the standard even–odd filling scheme in the Coulomb blockade regime can be easily obtained in a quantum dot containing two wells strongly coupled by a very transparent barrier. By exploiting a multi-gate configuration, we prove that a partial filling of nearly degenerate orbitals can be controlled electrostatically. Singlet–triplet spin transitions are demonstrated by low-temperature magneto-transport measurements.
Improved efficiency in organic/inorganic hybrid solar cells by interfacial modification of ZnO nanowires with small molecules
Authors: Chang Sehoon , Park Hyesung , Cheng Jayce J , Rekemeyer Paul H , Gradečak Silvija 
Published: September 2014

Abstract
We demonstrate improved photovoltaic performance of ZnO nanowire/poly(3-hexylthiophene) (P3HT) nanofiber hybrid devices using an interfacial modification of ZnO nanowires. Formation of cascade energy levels between the ZnO nanowire and P3HT nanofiber was achieved by interfacial modification of ZnO nanowires using small molecules tetraphenyldibenzoperiflanthene (DBP) and 3,4,9,10-perylenetetracarboxylic bisbenzimidazole (PTCBI). The successful demonstration of improved device performance owing to the cascade energy levels by small molecule modification is a promising approach toward highly efficient organic/inorganic hybrid solar cells.
Characterization and analysis of InAs/p–Si heterojunction nanowire-based solar cell
Authors: Mallorquí Anna Dalmau , Alarcón-Lladó Esther , Russo-Averchi Eleonora , Tütüncüoglu Gözde , Matteini Federico , Rüffer Daniel , Morral Anna Fontcuberta i 
Published: September 2014

Abstract
The growth of compound semiconductor nanowires on the silicon platform has opened many new perspectives in the area of electronics, optoelectronics and photovoltaics. We have grown a 1 × 1 mm2 array of InAs nanowires on p-type silicon for the fabrication of a solar cell. Even though the nanowires are spaced by a distance of 800 nm with a 3.3% filling volume, they absorb most of the incoming light resulting in an efficiency of 1.4%. Due to the unfavourable band alignment, carrier separation at the junction is poor. Photocurrent increases sharply at the surrounding edge with the silicon, where the nanowires do not absorb anymore. This is further proof of the enhanced absorption of semiconductors in nanowire form. This work brings further elements in the design of nanowire-based solar cells.
Magnetic properties, exchange coupling and novel stripe domains in bulk SrFe12O19/(Ni,Zn)Fe2O4 composites
Authors: Xia Ailin , Zuo Conghua , Zhang Lijiao , Cao Chunxiang , Deng Yong , Xu Wei , Xie Mingfu , Ran Songlin , Jin Chuangui , Liu Xianguo 
Published: September 2014

Abstract
Bulk SrFe12O19/(Ni0.4Zn0.6)Fe2O4 composite ferrites with mass ratios R
m = 2 : 1, 1 : 1 and 1 : 2 were prepared using nanopowders obtained via a hydrothermal method, and their phase composition, magnetic properties, exchange coupling (EC) and magnetic microstructures were systematically investigated. It is found that all the bulk specimens sintered at either 700 or 900 °C are composed of two phases but exhibit typical single-phase magnetic behaviours, indicating the existence of EC between the magnetically hard and soft phases. However, too much (R
m = 2 : 1) or too little (R
m = 1 : 2) soft (Ni0.4Zn0.6)Fe2O4 phase weakens the EC in the composites. It is also proved that except for the EC, the strengthening of chemical polarization of the internal chemical bonds affects saturation magnetization, and the size of nanoscale grains significantly influences the EC and magnetic properties. In addition, novel stripe domains are found in all of the bulk composite specimens, which could be ascribed to the magnetization of the soft (Ni,Zn)Fe2O4 phase induced by the hard SrFe12O19 phase.
β-Ga2O3 nanowires for an ultraviolet light selective frequency photodetector
Authors: López I , Castaldini A , Cavallini A , Nogales E , Méndez B , Piqueras J 
Published: September 2014

Abstract
The behaviour of β-Ga2O3 nanowires as photoconductive material in deep ultraviolet photodetectors to operate in the energy range 3.0–6.2 eV has been investigated. The nanowires were grown by a catalyst-free thermal evaporation method on gallium oxide substrates. Photocurrent measurements have been carried out on both undoped and Sn-doped Ga2O3 nanowires to evidence the influence of the dopant on the photodetector performances. The responsivity spectrum of single nanowires show maxima in the energy range 4.8–5.4 eV and a strong dependence on the pulse frequency of the excitation light has been observed for undoped nanowires. Our results show that the responsivity of β-Ga2O3 nanowires can be controlled by tuning the chopper frequency of the excitation light and/or by doping of the nanowires. Non-linear behaviour in characteristic current–voltage curves has been observed for Ga2O3 : Sn nanowires. The mechanism leading to this behaviour has been discussed and related to space-charged-limited current effects. In addition, the responsivity achieved by doped nanowires at lower bias is higher than for undoped ones.
Multi-species simulation of Trichel pulses in oxygen
Authors: Durán-Olivencia F J , Pontiga F , Castellanos A 
Published: September 2014

Abstract
The development of negative corona Trichel pulses in oxygen between a spherical cathode and a plane is investigated using a plasma chemical model of ten selected species, which includes electrons, ions and neutrals. The interaction among these species is described by a model that incorporates the most important plasma chemical processes, such as ionization, electron attachment and detachment, electron impact dissociation and excitation, and clustering. The spatio-temporal evolution of charged and neutral species and their reaction rates are evaluated along different moments during the pulses. The case of the first Trichel pulse is considered separately, since its characteristics clearly differ from the subsequent pulses. The results show that the negative space charge is constituted of different types of ions, depending on the stage of the pulse. Moreover, a spatial segregation of negative ions is observed during the post-pulse period. Regarding neutral species, ozone increases linearly with time, without being considerably affected by the occurrence of pulses.
The role of nanographitic phase on enhancing the electron field emission properties of hybrid granular structured diamond films: the electron energy loss spectroscopic studies
Authors: Kurian Joji , Sankaran Kamatchi Jothiramalingam , Thomas Joseph P , Tai N H , Chen Huang-Chin , Lin I-Nan 
Published: September 2014

Abstract
The electron field emission (EFE) properties of the hybrid granular structured diamond (HiD) films were markedly improved by N-ion implantation and annealing processes. The evolution of microstructure/bonding structure of the films due to these processes was investigated using the transmission electron microscopy (TEM) and the electron energy loss spectroscopy (EELS), respectively. The N-ion implanted/annealed HiD films showed a low turn-on field of (E
0)HiD = 7.4 V µm−1 with large current density of (J
e)HiD = 600 µA cm−2, at 17.8 V µm−1, compared with pristine HiD films ((E
0) = 10.3 V µm−1, (J
e) = 95 µA cm−2 at the same applied field). While the TEM studies revealed only the microstructural evolution due to N-ion implantation/annealing processes, the EELS elucidated the change in bonding structure, namely the transformation between the sp3-bonded carbons and the sp2-bonded ones. Therefore, the combined TEM/EELS analyses provided more insight into understand the mechanism by which the N-ion implantation/annealing processes enhanced the EFE properties of HiD films. These studies clearly demonstrated that the N-ion implantation/annealing processes induced the formation of nanographitic clusters. These nanographitic phases form an interconnected path throughout the film surface facilitating the easy transport of electrons and thereby markedly enhancing the EFE properties for the N implanted/annealed HiD films.
Traps and Thresholds in Pastoralist Mobility
Authors: Toth Russell 
Published: September 2014

AbstractThis article presents a new approach to identifying poverty traps in East African pastoralist communities. A flexible semiparametric estimation procedure is used to identify a bifurcation in the propensity to engage in the asset‐based, mobile herding livelihood, in comparison to the sedentary alternative, as a function of herd size. The identified threshold is consistent with previous evidence on poverty traps based on modeling herd stock dynamics. The approach contributes to an emerging literature that seeks to identify poverty traps through testing the implications of the posited behavioral mechanism behind the trap, as opposed to directly modeling asset dynamics. The approach is further employed to provide complementary evidence on the relationship between ability and assets in sustaining mobile pastoralism.
Death With Tuberculosis in California, 1994–2008
Authors: Pascopella Lisa , Barry Pennan M. , Flood Jennifer , DeRiemer Kathryn 
Published: September 2014

Abstract
Background.  Identifying factors associated with tuberculosis (TB) deaths will inform efforts to prevent deaths.
Methods.  We examined deaths among patients with culture-confirmed TB reported to the California TB Registry during 1994–2008. We calculated the age-adjusted percentage of deaths before and during TB treatment and estimated trends. We constructed multivariable logistic regression models to identify factors associated with death during treatment.
Results.  Of 40 125 patients with culture-confirmed TB, 4565 (11%) died: 1146 (25%) died before treatment started, and 3419 (75%) died during treatment. The age-adjusted percentage of patients who died before and during treatment declined from 1994 to 2008 (3.5% to 2%, and 10.4% to 7.2%, respectively, both P &lt; .0001). We identified several risk factors for death that may be addressed with public health efforts: acquired multidrug resistance (adjusted odds ratio [aOR] = 4.67; 95% confidence interval [CI], 2.09–10.45); care in the private sector (aOR = 3.08; 95% CI, 2.75–3.44); and an initial treatment regimen of &lt;3 drugs (aOR = 2.07; 95% CI, 1.63–2.64). We identified other risk factors for death that could be used as markers for intensified diagnostic and treatment processes in hospital: human immunodeficiency virus coinfection; meningeal, peritoneal, and disseminated TB; substance use; and abnormal chest radiograph without cavities.
Conclusions.  In California, 1 in 9 TB patients died with a potentially curable disease. Public health departments might prevent deaths in patients with TB by strengthening partnerships with private providers, intensifying diagnostic and treatment processes for patients at risk of death in hospital, optimizing treatment regimens for patients with comorbidities, and preventing the acquisition of drug resistance.
Cell-based Therapy for Acute Organ Injury
Authors: Monsel Antoine , Zhu Ying-gang , Gennai Stephane , Hao Qi , Liu Jia , Lee Jae W. 
Published: September 2014

Abstract
Critically ill patients often suffer from multiple organ failures involving lung, kidney, liver, or brain. Genomic, proteomic, and metabolomic approaches highlight common injury mechanisms leading to acute organ failure. This underlines the need to focus on therapeutic strategies affecting multiple injury pathways. The use of adult stem cells such as mesenchymal stem or stromal cells (MSC) may represent a promising new therapeutic approach as increasing evidence shows that MSC can exert protective effects following injury through the release of promitotic, antiapoptotic, antiinflammatory, and immunomodulatory soluble factors. Furthermore, they can mitigate metabolomic and oxidative stress imbalance. In this work, the authors review the biological capabilities of MSC and the results of clinical trials using MSC as therapy in acute organ injuries. Although preliminary results are encouraging, more studies concerning safety and efficacy of MSC therapy are needed to determine their optimal clinical use. (Anesthesiology 2014; 121:1099-121)
Factors governing filling of blind via and through hole in electroplating
Authors: Wang Jing , Wu Miao , Cui Chengqiang 
Published: September 2014

Purpose– The purpose of this paper is to present a clear picture of the key factors of blind via and through hole filling in electroplating, e.g. shape of via or hole, electroplating solution, process, as well as the developments of mechanisms and models.Design/methodology/approach– First, the paper details the development trends and challenges of via filling. Then the research status of mechanisms, electroplating solutions, including base solution and additives, numerical model and mass transfer is described. Finally, through hole filling is briefly reviewed.Findings– To achieve excellent via filling performance, the characteristics of the via or hole, the ratio of acid/copper, selection of additives and factors of mass transfer are comprehensively considered in terms of optimization of the electroplating process. It is beneficial to design vias with appropriate aspect ratios, to strengthen the adsorption of the accelerator in the via bottom, to inhibit the increase of surface copper thickness and to form butterfly-shaped copper in the centre of through holes. Optimized process parameters should be taken into consideration in superfilling.Originality/value– The paper reviews different sets of additives, mechanisms and superfilling models for state-of-the-art via filling and the developments of filling for through holes.
Transformational leadership and innovative work behavior
Authors: Afsar Bilal , F. Badir Yuosre , Bin Saeed Bilal 
Published: September 2014

Purpose– The purpose of this paper is to explore the mediating role of psychological empowerment and the moderating role of self-construal (independent and interdependent) on the relationship between transformational leadership and employees’ innovative work behavior (IWB).Design/methodology/approach– A total of 639 followers and 87 leaders filled out questionnaires from cross-industry sample of five most innovative companies of China. Structural equation modeling was used to analyze the relations.Findings– Results revealed that psychological empowerment mediated the relationship between transformational leadership and IWB. The research established that transformational leadership positively influences IWB which includes idea generation as well as idea implementation. The results also showed that the relationship between transformational leadership and IWB was stronger among employees with a higher interdependent self-construal and a lower independent self-construal.Originality/value– This study adds to IWB literature by empirically testing the moderating role of self-construal and the mediating role of psychological empowerment on transformational leadership-IWB link.