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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Synthesis and characterisation of group 15 materials and transition metal spinel oxides

Pickard, Laura Kay January 2000 (has links)
No description available.
22

Versatile Synthesis of Transition Metal Phosphides: Emerging Front-runners for Affordable Catalysis

Mattei, April C. 01 January 2016 (has links)
Transition metal phosphide materials have found themselves at the forefront of research revolving around energy applications. Due to the vast range of properties possessed by marginally different phase compositions, binary and ternary metal phosphides are utilized as catalysts, semi-conductors and magnetocaloric materials along with many others. These attractive properties, which are highly phase dependent, call for a versatile and cost effective synthesis route for various phosphide materials without sacrificing properties important at the nanoscale such as particle size and morphology. The primary focus outlined in the work of this dissertation pertains to a versatile wet chemical synthesis capable of producing multiple phases of binary and ternary phosphides containing one or more of the transition metals cobalt, iron and nickel. These metals were of particular interest due to the proven catalytic activity of iron, cobalt or nickel binary phases and the lack of research conducted on the corresponding ternary phases. The challenge presented by wet chemical synthesis methods is the ability to separate different crystal phases of metal phosphide in a short amount of time, with less toxic and lower cost chemicals, and a simple synthetic process with the ability to produce products on a larger scale. Oleylamine was used as a solvent, capping agent and reducing agent along with trioctylphosphine or triphenylphosphine as a phosphorus source. Many binary phosphide phases were synthesized with the same method and purity of phase was controlled primarily with temperature or phosphorus to metal ratio (P:M). At lower temperatures (290-320°C) or lower P:M (4:1) Ni3P,Ni2P, Fe2P, and Co2P were synthesized while higher temperatures (330-360°C) or higher P:M (22:1) produced Ni5P4, Ni12P5, FeP and CoP. Ternary phosphides FeCoP and CoNiP were also successfully synthesized at temperatures of 300-330°C with small excesses of phosphorus (2-5 molar excess). Preliminary catalytic studies for the evolution of hydrogen gas were conducted to test the efficacy of phosphide materials produced via the simplistic oleylamine method. Ni2P was found to have the highest activity toward hydrogen evolution with an overpotential of 320 mV which is comparable and in some cases better than other unsupported phosphide catalysts of the same phase. The ability to control phase composition using a simple, cost effective wet chemical synthesis is promising for the future production of active metal phosphide materials.
23

High electric field current transport in semi-insulating GaAs and InP

Luo, Yilin. January 2000 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 230-253).
24

Positron annihilation spectroscopic studies of GAAS and INP related systems

凌志聰, Ling, Chi-chung, Francis. January 1996 (has links)
published_or_final_version / Physics / Doctoral / Doctor of Philosophy
25

Studies of iron acceptors in indium phosphide by photoconductivity andphotoluminescence techniques

伍寶洪, Ng, Po-hung. January 1990 (has links)
published_or_final_version / Physics / Doctoral / Doctor of Philosophy
26

Electrical transport properties of n-Type InP

Beaudoin, Mario January 1988 (has links)
InP obtained by metal-organic vapor phase epitaxy, with properties similar to GaAs, shows mobilities approaching the theoretical maxima at low temperatures. However, the corresponding values remain abnormally low at room temperature where a pronounced electronic excitation to the conduction band is observed simultaneously. This reduction of the mobility is attributed to the presence of deep centers that are electrically inactive at low temperatures but become excited when the temperature increases. A model based on an iterative solution to the Boltzmann equation and accounting for the usual scattering mechanisms, including inelastic interactions, is able to explain the data perfectly and shows that a very high mobility at low temperature is not a sufficient measure of the purity for this material. The binding energy of the deep centers depends on the organo-metalic source used for the growth. This links the solution of this problem to the purification of the chemicals. Depletion effects at the interfaces did not appear to be significant. (Abstract shortened by UMI.)
27

GSMBE growth on V-groove patterned substrates for InP-based quantum wires /

Wang, Jun. January 1997 (has links)
Thesis (Ph.D) -- McMaster University, 1997. / Includes bibliographical references (leaves 130-139). Also available via World Wide Web.
28

Physical InP-based HBT models for ultimate digital circuit optimization /

Ruiz Palmero, José Miguel. January 2006 (has links)
Techn. Hochsch., Diss.--Zürich, 2006.
29

Positron annihilation spectroscopic studies of GAAS and INP related systems /

Ling, Chi-chung, Francis. January 1996 (has links)
Thesis (Ph. D.)--University of Hong Kong, 1996. / Includes bibliographical references (leaf 217-227).
30

Phosphanylborhydride und Chalkogenphosphanylborhydride

Dornhaus, Franz Ralf. Unknown Date (has links)
Universiẗat, Diss., 2007--Frankfurt (Main).

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