bluuebunny/crossref_metadata_2025_split huggingface dataset:
Histopathologic features of atypical glands on prostate biopsy: Nucleolar size is a predictor of subsequent detection of prostatic adenocarcinoma
Authors: Venigalla Sriram , Zhao Chen , Miyamoto Hiroshi 
Published: August 2012

AbstractBACKGROUNDPatients whose prostate biopsy reveals the presence of atypical glands suspicious for carcinoma (AGSC) are subject to close monitoring and repeat biopsies, perhaps unnecessarily, as clinicians do not have a clear basis for understanding and stratifying the significance of these findings.METHODSIn a retrospective, blinded manner, we histopathologically examined initial biopsies reported as AGSC (82 patients, 93 foci). On subsequent biopsies, 31 (38%)/5 (6%) patients were found to have prostate cancer (PCA)/AGSC, respectively, while no carcinoma (NOCA) was identified in the remainder (56%) of cases.RESULTSNucleolar grade (on a scale of 1–4 with “1” denoting small, inconspicuous nucleoli and “4” denoting macronucleoli) was significantly higher in PCA cases than in NOCA cases whether comparing all AGSC foci (P = 0.006) or when considering the highest grade in each patient (P = 0.009). However, the number of AGSC per focus was similar (P = 0.926) between PCA (mean ± SD: 7.03 ± 5.35) and NOCA (mean ± SD: 7.13 ± 4.44). Adjacent (P = 0.117) and separate (P = 0.457) high‐grade prostatic intraepithelial neoplasia was found in 8/37 (22%) foci and 12/31 (39%) cases in PCA, respectively, and in 4/48 (8%) foci and 13/46 (28%) cases in NOCA, respectively. The presence of intraluminal dense secretion, crystalloid, or mucin in AGSC did not show a statistically significant correlation between PCA [5/37 (14%)] and NOCA [10/48 (21%)] (P = 0.567).CONCLUSIONSOur study may thus clarify the significance of AGSC on prostate biopsy and suggests that the size of nucleoli in AGSC is a positive predictor of subsequent detection of prostatic adenocarcinoma. Prostate 73: 376–381, 2013. © 2012 Wiley Periodicals, Inc.
Analysis of an optical biosensor based on elastic light scattering from diamond‐, glass‐, and sapphire microspheres
Authors: Murib Mohammed S. , Tran Anh Quang , De Ceuninck Ward , Schöning Michael J. , Nesládek Milos , Serpengüzel Ali , Wagner Patrick 
Published: August 2012

AbstractDeoxyribonucleic acid (DNA) and protein recognition are now standard tools in biology. In addition, the special optical properties of microsphere resonators expressed by the high quality factor (Q‐factor) of whispering gallery modes (WGMs) or morphology dependent resonances (MDRs) have attracted the attention of the biophotonic community. Microsphere‐based biosensors are considered as powerful candidates to achieve label‐free recognition of single molecules due to the high sensitivity of their WGMs. When the microsphere surface is modified with biomolecules, the effective refractive index and the effective size of the microsphere change resulting in a resonant wavelength shift. The transverse electric (TE) and the transverse magnetic (TM) elastic light scattering intensity of electromagnetic waves at 600 and 1400 nm are numerically calculated for DNA and unspecific binding of proteins to the microsphere surface. The effect of changing the optical properties was studied for diamond (refractive index 2.34), glass (refractive index 1.50), and sapphire (refractive index 1.75) microspheres with a 50 µm radius. The mode spacing, the linewidth of WGMs, and the shift of resonant wavelength due to the change in radius and refractive index, were analyzed by numerical simulations. Preliminary results of unspecific binding of biomolecules are presented. The calculated shift in WGMs can be used for biomolecules detection.
Luminescence properties of stoichiometric EuM2S4 (M = Ga, Al) conversion phosphors for white LED applications
Authors: Yu Ruijin , Yang Hyun Kyoung , Moon Byung Kee , Choi Byung Chun , Jeong Jung Hyun 
Published: August 2012

AbstractEuM2S4 (M = Ga, Al) phosphors were synthesized using the solid‐state reaction method. The structure and photoluminescence (PL) properties of the phosphors were investigated in detail. XRD pattern results indicated that the two phosphors are isostructures to the orthorhombic structure. The PL spectra showed that the EuGa2S4 and EuAl2S4 phosphors can be excited efficiently by UV–visible light from 350 to 480 nm and that they emit intense green and bluish‐green light, with emission bands peaking at 545 and 506 nm, respectively. The fluorescence lifetimes of Eu2+ were calculated to be 0.076 and 0.064 µs for EuGa2S4 and EuAl2S4, respectively. The thermal quenching temperature was 412 K for EuGa2S4. A green LED was fabricated by the combination of a near‐UV InGaN chip and the prepared EuGa2S4 phosphor. The EuGa2S4 phosphor exhibits much better green color purity than EuAl2S4. As a result, EuGa2S4 might be a promising green phosphor candidate for solid‐state lighting LED technology.
Erratum: Evaluation of the bond polarizabilities of zincblende‐type semiconductors: Application to the Raman spectra of disordered GaSb/AlSb (001) superlattices [Phys. Status Solidi B 249, No. 8, 1521–1530 (2012)]
Authors: Berdekas D. , Ves S. 
Published: August 2012

AbstractEquations with reference to the zinc blende primitive cell volume are slightly changed.
Photoluminescence properties of carbon‐doped β‐FeSi2 nanocrystals
Authors: Maeda Yoshihito , Nishimura Kentaro , Nakajima Takahito , Matsukura Bui , Narumi Kazumasa , Sakai Seiji 
Published: August 2012

AbstractWe report enhancement of intrinsic photoluminescence (PL) from β‐FeSi2 nanocrystals by doping carbon. In the appropriate dose of C60+ ion implantation into the average nanocrystal size of 14 nm, the PL intensity was enhanced by 260% and increase of the exciton binding energy of 1.8 meV in comparison with that of the non‐doped nanocrystal. Furthermore, we found that there was a clear correlation between the PL enhancement and increase of the exciton binding energy. This important result suggests that carbon atoms doped in the silicide lattice may play as an isoelectronic trap and probably form bound excitons with stable states as predicted theoretically. We found a new mechanism of the PL enhancement for β‐FeSi2 nanocrystals. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrical activity of multivacancy defects in silicon
Authors: Santos P. , Coutinho J. , Rayson M. J. , Briddon P. R. 
Published: August 2012

AbstractThe formation processes and properties of multivacancy defects in Si have been recently the subject of several re‐search studies. Here we report on density functional calculations concerning the stability and electrical activity of the tetravacancy, pentavacancy and hexavacancy complexes in Si. Formation energy calculations indicate that Four‐Fold Coordinated (FFC) V4 and V5 are more stable than Part‐of‐Hexagonal‐Ring (PHR) or planar structures by at least 1.2 eV and 0.6 eV, respectively. This relative stability order between configurations remains unchanged for different charged states from double plus to double minus. Calculations of the electrical activity predict deep acceptor levels for the FFC defects. Accordingly, electron traps related to (–/0) and (=/–) levels near Ec – 0.5 eV were found for V4 and V5, whereas levels for V6 were estimated at Ec – 0.35 eV. No donor levels were found for these defects. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Scattering tensors and optical transitions in Si and Ge
Authors: Kunert H. W. , Machatine A. G. J. , Niyongabo P. , Govender M. , Mwakikunga B. W. 
Published: August 2012

AbstractThe selection rules (SR's) for the Kronecker product (KP) of Si and Ge irreducible representations (irreps) are required to determine the intervalley scattering processes. The SR's for transitions between the lowest conduction band minima at Γ, X and L high symmetry points and the highest maximum of the valence band (VB) in the Brillouin zone of O7h space group symmetry are determined. The symmetry of phonons due to electron‐phonon (El‐Ph) interaction follows from the KP's: L1 ⊗ Γ12(Γ2–), Δ1 Γ12(Γ2–), L1(L1+) ⊗ Δ1 for Ge and L1 ⊗ Γ15(Γ4–), Δ ⊗ Γ15(Γ4–), L1(L1+) ⊗ Δ1 for Si. The elements of El‐Ph scattering tensors are linear combinations of the Clebsch‐Gordon coefficients (CGC's). Here we have computed the coupling coefficients relevant to scattering tensors. Our theoretical results confirm the available experimental data. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Enhancement of IR light emission from β‐FeSi2 nanocrystals embedded in Si
Authors: Maeda Yoshihito , Nishimura Kentaro , Nakajima Takahito , Matsukura Bui , Narumi Kazumasa , Sakai Seiji 
Published: August 2012

AbstractWe have systematically investigated photoluminescence (PL) properties of β‐phase nanocrystals which are formed by a phase transition from metastable γ‐FeSi2 with a Fluorite structure to β‐FeSi2, and succeeded in enhancement of the PL intensity in the optimum conditions of double annealing process. For the PL enhancement, the time of postannealing at 800 °C is dominated by the time of the preannealing at 400 or 500 °C which is related to amount of the γ‐phase. After discussing some possible factors, we speculate that the PL enhancement observed in this study may be attributed mainly to improvement of the interface condition between the nanocrystal and Si, because the crystallographic epitaxial relationship among the phases, Si(111)//γ(111)//β(202)/(220) can be maintained during precipitation of the nanocrystal on Si(111). (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preparation of large step‐free mesas on Si(111) by molecular beam epitaxy
Authors: Fissel Andreas , Krügener Jan , Osten H. Jörg 
Published: August 2012

AbstractDevelopment of surface morphology in Si molecular beam epitaxy on mesa‐structured Si(111) at temperatures around the (7x7) –“1x1” surface phase transition was studied using atomic force microscopy. Significant changes in surface morphology were found for a small increase in temperature near the surface phase transition accompanied by a strong increase in step‐free area dimension. This will be discussed with regard to the simultaneous appearance of the two surface phases under certain condition and their specific influence on the growth behaviour. Small triangular islands and voids appeared after growth at 1080 K indicating surface instability of larger step‐free areas. Growth at 1120 K with a rate of 1 nm/min results in the formation of atomically step‐free surface over 10x10 µm2 mesas without any irregularities. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Defects in p‐type Cz‐silicon irradiated at elevated temperatures
Authors: Ganagona Naveengoud , Raeissi Bahman , Vines Lasse , Monakhov Edouard V. , Svensson Bengt G. 
Published: August 2012

AbstractP‐type Czochralski grown (Cz) silicon samples have been irradiated at room temperature (RT), 350, and 450 °C with 1.8 MeV protons to doses of 2×1012and 1×1013 cm‐2 and analyzed by deep level transient spectroscopy (DLTS). The generation rate of interstitial carbon–interstitial oxygen (CiOi) increases with the irradiation temperature, suggesting less efficient annihilation of self‐interstitials and mono‐vacancies at elevated temperature. A defect located at ∼Ev+0.39 eV (Ev denotes the valence band edge) appears in the sample irradiated at 450 °C and also emerges at the expense of CiOi center in the sample irradiated at RT and subsequently heat‐treated above 400 °C. The amplitude of this level is enhanced in the sample irradiated at 450 °C. By comparing the annealing behavior found by photoluminescence (PL) measurements and reported theoretical predictions, the ∼Ev+0.39 eV level is tentatively assigned to the interstitial carbon–oxygen dimer (CiO2i). In addition, other levels at ∼Ev+0.34 eV and ∼Ev+0.58 eV are observed in samples irradiated at 450 °C and RT with heat treatment in the range of 400‐500 °C (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Non‐destructive characterization of saw damage in silicon photovoltaics substrates by means of photomodulated optical reflectance
Authors: Bogdanowicz J. , Mertens P. W. , Cornagliotti E. , Wostyn K. , Penaud J. , Jaffrennou P. , Abric E. , Vandervorst W. 
Published: August 2012

AbstractIn order to minimize the considerable loss of Si material during the processing of a silicon photovoltaics (PV) substrate into a solar cell, the optimization of the saw damage (SD) removal is an important step. The PV cell process therefore requires a routine metrology solution suitable to probe the SD present in the substrate. Though cross‐sectional Transmission Electron Microscopy is typically used for this purpose, this technique is not suited for in‐line measurements. It is furthermore destructive, time‐consuming and limited to very small sampling volumes. In this paper, we demonstrate the capabilities of the Photomodulated Optical Reflectance (PMOR) method for the in‐line measurement of SD. PMOR is a laser‐based pump‐probe technique, wherein the probe laser measures the reflectance of the sample (DC reflectance) as well as the change in reflectance (AC reflectance) which the pump laser has induced by optically injecting excess carriers and heat. As PMOR is a local and nondestructive technique, it offers a very promising approach for the simultaneous characterization of roughness and SD. We demonstrate the versatility of this approach and the response of the DC and AC reflectances when studying wafers which have undergone successive etchings to remove the SD sequentially (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of the hydrogen flow rate on the structural and optical properties of hydrogenated amorphous silicon thin films prepared by plasma enhanced chemical vapor deposition
Authors: Ben Amor Sana , Dimassi Wissem , Ali Tebai Mohamed , Ezzaouia Hatem 
Published: August 2012

AbstractHydrogenated amorphous silicon (a‐Si:H) thin films were deposited from pure silane (SiH4) and hydrogen (H2) gas mixture by plasma enhanced chemical vapor deposition (PECVD) method at low temperature (400 °C) using high rf power (60 W). The structural and optical properties of these films are systematically investigated as a function of the flow rate of hydrogen (F).The surface morphology is analyzed by atomic force microscopy (AFM). The characterization of these films with low angle X‐ray diffraction revealed that the crystallite size in the films tends to decrease with increase in (F). The Fourier transform infrared (FTIR) spectroscopic analysis showed that at low values of (F), the hydrogen is predominantly incorporated in Si:H films in di‐hydrogen (Si‐H2) and (Si‐H2)n complexes. However, with increasing (F) the hydrogen bonding in Si:H films shifts from di‐hydrogen (Si‐H2) and (Si‐H2)n complexes to the mono‐hydrogen (Si‐H) bonding configuration. Finally, for these optimized conditions, the deposition rate decreases with increasing F (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Raman scattering study on hydrogen‐induced defects in silicon used in the ion‐cut process
Authors: Socher S. , Lavrov E. V. , Weber J. 
Published: August 2012

AbstractIon implantation is a widely used technique in the fabrication of semiconductor devices. We present a Raman scattering study of single crystalline silicon implanted with 28Si ions and subsequently treated in a hydrogen plasma. This treatment generates hydrogen molecules with a Raman signal at 3830 cm–1. The same band is detected in hydrogen implanted silicon employed in the ion‐cut technology.The band reveals a substructure, which is assigned to the ro–vibrational transitions of H2 trapped at three different sites of the silicon lattice. The H2 signals are shown to correlate with the Si–H vibrational modes at 1888, 1930 and 1964 cm–1 which indicates the interstitial–type nature of the traps for the molecules. The properties of the traps are discussed. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the impact of interfacial SiOx‐layer on the passivation properties of PECVD synthesized aluminum oxide
Authors: Laades Abdelazize , Sperlich Hans‐Peter , Bähr Mario , Stürzebecher Uta , Diaz Alvarez Carlos A. , Burkhardt Markus , Angermann Heike , Blech Michael , Lawerenz Alexander 
Published: August 2012

AbstractThe interface passivation of a ‐AlOx/a ‐SiNx:H stacks deposited on p‐type silicon by plasma enhanced chemical vapor deposition is investigated by means of charge carrier lifetime and surface photovoltage measurements. To control the quality of the interface, we performed different surface preparation steps prior to a ‐AlOx/a ‐SiNx:H stack deposition. Our investigation is focussing on the interface passivation upon post‐deposition thermal treatments such as annealing at 425 °C and firing as applied in the silicon solar cell industry. We demonstrate that the interface recombination is mainly controlled by the interface state density as demonstrated by lifetime and SPV measurements. The increase of the negative charge density after thermal steps as revealed by FTIR spectroscopy evidences that the field effect has at least an enhancing effect in improving the passivation level (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Detailed investigation of the structural and passivation properties of silicon oxynitrides for silicon solar cells
Authors: Laades Abdelazize , Burkhardt Markus , Roczen Maurizio , Klimm Carola , Blech Michael , Lawerenz Alexander 
Published: August 2012

AbstractWe investigated the structural and passivation properties of hydrogenated amorphous silicon oxynitrides (a ‐SiOxNy:H) prepared by plasma enhanced chemical vapor deposition. Using energy dispersive X‐ray analysis and X‐ray photoelectron spectroscopy, we determined the stoichiometry x = [O]/[Si] and y = [N]/[Si] in the whole range extending from a ‐Si:H (x, y =0) to SiO2 (x ∼2, y ∼0). To analyze the thermal stability, test samples were subjected to high temperature firing in the range 850 to 950 °C. Charge carrier lifetime measurements revealed that Si‐rich a ‐SiOxNy:H feature excellent surface passivation on p‐type CZ silicon in the as‐deposited state. After firing, a ‐SiOx/a ‐SiNy:H stacks with near‐stoichiometric a ‐SiOx showed an outstanding thermal stability. A fine tracing of the density and spectral position of the Si‐O‐Si stretching vibration by means of the Fourier transform infrared spectroscopy revealed valuable information on the incorporation of oxygen and nitrogen atoms during deposition. Accordingly, we found that a high density of Si‐O‐Si bonds approaching the characteristic frequencies of thermal SiO2 and silica (1075 to 1080 cm–1) is clearly correlated to the interface passivation quality. Due to hydrogen migration from an a ‐SiNy:H cap layer induced by firing, the a ‐SiO2/a ‐SiNy:H system feature passivation properties close to thermally grown silicon oxide (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrical and optical characterization of extended defects in silicon mono‐cast material
Authors: Moralejo B. , Tejero A. , Hortelano V. , Martínez O. , Jiménez J. , Parra V. 
Published: August 2012

AbstractMono‐cast Si growth is currently a very promising approach to optimize the cost per watt in the production of PV devices, simultaneously increasing the installed energy/m2 ratio. However, due to the novelty of this growth approach, the material properties have not yet been studied in detail. In this work, by combining PL imaging with electrical characterization techniques (LBIC and EBIC), both the large scale and the local properties of the wafers grown from mono‐cast Si ingots have been analyzed. PL imaging shows two kinds of defects, which were studied in detail by LBIC. Electrical active defects are found in areas corresponding to a unique large grain, assigned to sub‐GBs, decorated by impurities. These defects have strong charge trapping, with deleterious consequences for the device performance. The presence of those intra‐grain defects is also confirmed by EBIC maps, which allows comparing the electrical activity of both grain and sub‐grain boundaries (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Local structural phase determination of Ni silicide thin films using EXAFS
Authors: Sahiner M. A. , Hung P. Y. , Loh W.‐Y. , Lysaght P. S. , Woicik J. C. , Guerrero D. 
Published: August 2012

AbstractThe local structural characterization of novel contact materials (nickel silicides) on N2+ implanted Si(100) substrates have been performed using Extended X‐ray‐Absorption Fine‐Structure Spectroscopy (EXAFS). The crystal phases of nickel silicides that are stabilized on Si (100) substrates (NiSi or NiSi2) upon varying implantation and post deposition annealing conditions were identified. The questions addressed are whether the final stabilized crystal phases of the nickel silicide layers could be identified and the fraction of the various crystal symmetries could be determined. The identification of the stabilized crystal phases in the nickel silicide formation process is crucial, as it was shown that a Si rich Ni silicide layer at the NiSix/Si interface causes a significant reduction in the electron Schottky barrier height (SBH). EXAFS analyses using experimental and theoretical references were performed on nickel silicide thin films on silicon substrates exposed to different N2+ ion doses prior to nickel deposition and silicidation processes. Using EXAFS analyses, the stabilized phases (e.g. NiSi vs. NiSi2, etc.) and their ratios were determined. EXAFS was proved to be sensitive to the subtle modifications of the crystal structures introduced by these modifications in the processing conditions. EXAFS analyses of the experimental reference structures (NiSi, NiSi2 powder samples) clearly exhibited the robust differences in the Fourier Transformed (FT) EXAFS data in the first shell region. EXAFS fits using theoretical structures corresponding to NiSi and NiSi2 symmetries have successfully identified the distinct crystal phases present in nickel silicide thin films subjected to different doses of N2+ ion implantation. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Epitaxial Si, SiGe and Ge on binary and ternary rare earth oxide buffers
Authors: Dargis Rytis , Arkun Erdem F. , Roucka Radek , Smith Robin , Williams David , Clark Andrew , Lebby Michael 
Published: August 2012

AbstractLattice engineering by combining multilayer binary (Gd2O3 and La2O3) and ternary (ErxNd1‐x)2O3 rare earth oxide layers makes possible the accommodation of lattice mismatch between the silicon substrate and the grown semiconductor layer for semiconductor on insulator structures leading to a reduction of defect density. It also opens up the opportunity for stress engineering and the avoidance of the formation of structural defects and mechanical damages caused by different thermal‐mechanical properties of the substrate and the layers. In this work, some results of the development of epitaxial heterostructures with group IV semiconductors (Si, SiGe and Ge) on rare earth oxide buffer layers grown on Si(111) are desribed. Distributed Bragg reflectors designed with only three pairs exhibits 80% reflectivity for blue light. On ternary erbium neodymium oxide, SiGe layer grows with a 5x5 reconstructed surface and a roughness of 1.7 nm. We demonstrate a crack free 1 µm thick epitaxial single crystal Ge layer grown on a pseudomorphic cubic La2O3 layer. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Strain distribution in GaAs/Si quantum wires
Authors: Tchelidze Tamar , Davydok Anton 
Published: August 2012

AbstractWe calculated displacement and stress field, as well as strain energy for GaAs nanowires grown on Si substrate. For calculations variational method was used. For radial coordinate dependence polynomial dependence (with linear and quadratic terms) and for vertical coordinate dependence exponential functions are taken inside the wire region. Radial and vertical displacements decreases as 1/r with increasing radial coordinate in substrate outside the wire region (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)