Search Results - (Author, Cooperation:P. Visconti)
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1Latest Papers from Table of Contents or Articles in PressD. P. Tittensor ; M. Walpole ; S. L. Hill ; D. G. Boyce ; G. L. Britten ; N. D. Burgess ; S. H. Butchart ; P. W. Leadley ; E. C. Regan ; R. Alkemade ; R. Baumung ; C. Bellard ; L. Bouwman ; N. J. Bowles-Newark ; A. M. Chenery ; W. W. Cheung ; V. Christensen ; H. D. Cooper ; A. R. Crowther ; M. J. Dixon ; A. Galli ; V. Gaveau ; R. D. Gregory ; N. L. Gutierrez ; T. L. Hirsch ; R. Hoft ; S. R. Januchowski-Hartley ; M. Karmann ; C. B. Krug ; F. J. Leverington ; J. Loh ; R. K. Lojenga ; K. Malsch ; A. Marques ; D. H. Morgan ; P. J. Mumby ; T. Newbold ; K. Noonan-Mooney ; S. N. Pagad ; B. C. Parks ; H. M. Pereira ; T. Robertson ; C. Rondinini ; L. Santini ; J. P. Scharlemann ; S. Schindler ; U. R. Sumaila ; L. S. Teh ; J. van Kolck ; P. Visconti ; Y. Ye
American Association for the Advancement of Science (AAAS)
Published 2014Staff ViewPublication Date: 2014-10-04Publisher: American Association for the Advancement of Science (AAAS)Print ISSN: 0036-8075Electronic ISSN: 1095-9203Topics: BiologyChemistry and PharmacologyComputer ScienceMedicineNatural Sciences in GeneralPhysicsKeywords: *Biodiversity ; *Conservation of Natural Resources ; *Extinction, BiologicalPublished by: -
2Latest Papers from Table of Contents or Articles in PressG. Pe'er ; L. V. Dicks ; P. Visconti ; R. Arlettaz ; A. Baldi ; T. G. Benton ; S. Collins ; M. Dieterich ; R. D. Gregory ; F. Hartig ; K. Henle ; P. R. Hobson ; D. Kleijn ; R. K. Neumann ; T. Robijns ; J. Schmidt ; A. Shwartz ; W. J. Sutherland ; A. Turbe ; F. Wulf ; A. V. Scott
American Association for the Advancement of Science (AAAS)
Published 2014Staff ViewPublication Date: 2014-06-07Publisher: American Association for the Advancement of Science (AAAS)Print ISSN: 0036-8075Electronic ISSN: 1095-9203Topics: BiologyChemistry and PharmacologyComputer ScienceMedicineNatural Sciences in GeneralPhysicsKeywords: Agriculture/*trends ; *Biodiversity ; *European Union ; *PolicyPublished by: -
3Latest Papers from Table of Contents or Articles in PressL. N. Joppa ; B. O'Connor ; P. Visconti ; C. Smith ; J. Geldmann ; M. Hoffmann ; J. E. Watson ; S. H. Butchart ; M. Virah-Sawmy ; B. S. Halpern ; S. E. Ahmed ; A. Balmford ; W. J. Sutherland ; M. Harfoot ; C. Hilton-Taylor ; W. Foden ; E. Di Minin ; S. Pagad ; P. Genovesi ; J. Hutton ; N. D. Burgess
American Association for the Advancement of Science (AAAS)
Published 2016Staff ViewPublication Date: 2016-04-23Publisher: American Association for the Advancement of Science (AAAS)Print ISSN: 0036-8075Electronic ISSN: 1095-9203Topics: BiologyChemistry and PharmacologyComputer ScienceMedicineNatural Sciences in GeneralPhysicsKeywords: Animals ; *Biodiversity ; Datasets as Topic/*standards ; Endangered Species/*statistics & numerical data ; Human Activities ; HumansPublished by: -
4Latest Papers from Table of Contents or Articles in PressL. N. Joppa ; P. Visconti ; C. N. Jenkins ; S. L. Pimm
American Association for the Advancement of Science (AAAS)
Published 2013Staff ViewPublication Date: 2013-09-07Publisher: American Association for the Advancement of Science (AAAS)Print ISSN: 0036-8075Electronic ISSN: 1095-9203Topics: BiologyChemistry and PharmacologyComputer ScienceMedicineNatural Sciences in GeneralPhysicsKeywords: *Biodiversity ; *Conservation of Natural Resources ; *PlantsPublished by: -
5Articles: DFG German National LicensesGigli, G. ; Rinaldi, R. ; Turco, C. ; Visconti, P. ; Cingolani, R.
Woodbury, NY : American Institute of Physics (AIP)
Published 1998Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: We report a flexible method for the patterning of organic semiconductors in the submicrometer range, which we have successfully applied to thin films of poly(p-phenylene vinylene) (PPV) prepared on a variety of substrates, such as quartz, indium–tin oxide coated glass, or inorganic dielectric mirrors. The method is based on holographic lithography performed by a corner cube interferometer of our own design and construction, followed by Ar-ion etching. © 1998 American Institute of Physics.Type of Medium: Electronic ResourceURL: -
6Articles: DFG German National LicensesJones, K. M. ; Visconti, P. ; Yun, F. ; Baski, A. A. ; Morkoç, H.
Woodbury, NY : American Institute of Physics (AIP)
Published 2001Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: Inversion domains in III-nitride semiconductors degrade the performance of devices fabricated in them. Consequently, it is imperative that we understand their electrostatic manifestation, the growth conditions under which such domains form, and an effective means of their identification. In what is nominally referred to as Ga-polarity samples, N-polarity domains have a polarization that is reversed with respect to the remainder of the surface, and therefore, have a different potential under strain. We have used surface-potential electric-force microscopy (SP-EFM) to image the electrostatic surface potential of GaN grown on sapphire, which is strained due to the thermal mismatch between the substrate and GaN. Employing a control sample with side-by-side Ga- and N-polarity regions, we have established the EFM mode necessary to identify inversion domains on GaN samples grown by molecular-beam epitaxy. This method is not sensitive to topology and has a spatial resolution of under 100 nm. The measured surface potentials for Ga-face and N-face regions are +25±10 and −30±10 mV, respectively, with respect to the sapphire substrate, where the sign is consistent with Ga- and N-polarity GaN under compressive strain due to thermal mismatch with the sapphire substrate. © 2001 American Institute of Physics.Type of Medium: Electronic ResourceURL: -
7Articles: DFG German National LicensesVisconti, P. ; Jones, K. M. ; Reshchikov, M. A. ; Yun, F. ; Cingolani, R. ; Morkoç, H.
Woodbury, NY : American Institute of Physics (AIP)
Published 2000Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: A free-standing 300-μm-thick GaN template grown by hydride vapor phase epitaxy has been characterized for its structural and optical properties using x-ray diffraction, defect delineation etch followed by imaging with atomic force microscopy, and variable temperature photoluminescence. The Ga face and the N face of the c-plane GaN exhibited a wide variation in terms of the defect density. The defect concentrations on Ga and N faces were about 5×105 cm−2 for the former and about 1×107 cm−2 for the latter. The full width at half maximum of the symmetric (0002) x-ray diffraction peak was 69 and 160 arc sec for the Ga and N faces, respectively. That for the asymmetric (10–14) peak was 103 and 140 arc sec for Ga and N faces, respectively. The donor bound exciton linewidth as measured on the Ga and N faces (after a chemical etching to remove the damage) is about 1 meV each at 10 K. Instead of the commonly observed yellow band, this sample displayed a green band, which is centered at about 2.44 eV. © 2000 American Institute of Physics.Type of Medium: Electronic ResourceURL: -
8Articles: DFG German National LicensesHuang, D. ; Visconti, P. ; Jones, K. M. ; Reshchikov, M. A. ; Yun, F. ; Baski, A. A. ; King, T. ; Morkoç, H.
Woodbury, NY : American Institute of Physics (AIP)
Published 2001Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: The polarity of GaN films grown using GaN and AlN buffer layers on sapphire substrates by molecular beam epitaxy were investigated by atomic force microscopy, hot wet chemical etching, and reflection high-energy electron diffraction. We found that the GaN films grown on high temperature AlN (〉890 °C) and GaN (770–900 °C) buffer layers invariably show Ga and N polarity, respectively. However, the films grown using low temperature (∼500 °C) buffer layers, either GaN or AlN, could have either Ga or N polarity, depending on the growth rate of the buffer layer. © 2001 American Institute of Physics.Type of Medium: Electronic ResourceURL: -
9Articles: DFG German National LicensesVisconti, P. ; Jones, K. M. ; Reshchikov, M. A. ; Cingolani, R. ; Morkoç, H.
Woodbury, NY : American Institute of Physics (AIP)
Published 2000Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: Defects in GaN layers grown by hydride vapor-phase epitaxy have been investigated by photoelectrochemical (PEC) etching, and by wet etching in hot H3PO4 acid and molten potassium hydroxide (KOH). Threading vertical wires (i.e., whiskers) and hexagonal-shaped etch pits are formed on the etched sample surfaces by PEC and wet etching, respectively. Using atomic-force microscopy, we find the density of "whisker-like" features to be 2×109 cm−2, the same value found for the etch-pit density on samples etched with both H3PO4 and molten KOH. This value is comparable to the dislocation density obtained in similar samples with tunneling electron microscopy, and is also consistent with the results of Youtsey and co-workers [Appl. Phys. Lett. 73, 797 (1998); 74, 3537 (1999)]. © 2000 American Institute of Physics.Type of Medium: Electronic ResourceURL: -
10Articles: DFG German National LicensesReshchikov, M. A. ; Visconti, P. ; Morkoç, H.
Woodbury, NY : American Institute of Physics (AIP)
Published 2001Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: We have studied the broad blue band, which emerges in the photoluminescence (PL) spectrum of c-plane GaN layers after etching in hot H3PO4 and subsequent exposure to air. This band exhibited a 100 meV blueshift with increasing excitation intensity and a thermal quenching with activation energies of 12 and 100 meV. These observations led us to suggest that surface states may be formed on etched surfaces and cause bandbending, which leads to a shift in transition energy with excitation. The blue PL is related to transitions from the shallow donors filled with nonequilibrium electrons to the surface states, which capture the photogenerated holes. The observed irreversible bleaching of the blue luminescence may be attributed to the metastable nature of the surface states or to the oxygen desorption. © 2001 American Institute of Physics.Type of Medium: Electronic ResourceURL: -
11Articles: DFG German National LicensesAlbini, A. ; Zhu, Z. ; Percario, M. ; Fassina, G.F. ; Toffenetti, J. ; Chader, G.J. ; Visconti, P. ; Noonan, D.
Amsterdam : ElsevierStaff ViewISSN: 0309-1651Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: BiologyType of Medium: Electronic ResourceURL: