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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.
71

Theory of the electronic states of semiconductor heterostructures

Coles, Richard A. January 1999 (has links)
This thesis is concerned with theoretical calculations of the properties of electronic bound states in semiconductor heterostructures. The complex band structure empirical pseudopotential method (EPM) is used as the foundation of the work. Spin orbit coupling and strain effects (due to lattice mismatch) are included in familiar ways, as is the transfer matrix method, allowing the study of arbitrarily configured heterostructures. These techniques are used to investigate the unusually deep InAs/AlSb conduction band well. The strong possibility of intraband transitions at electro magnetic wavelengths around 1.55µm is predicted, with corresponding enhanced momentum matrix elements and joint density of states over interband transitions. An InAs/GaSb/AlSb asymmetric well is investigated, paying particular attention to the bound states in the vicinity of the InAs/GaSb band overlap. The electron-like states are found to cross with heavy hole and anti-cross with light hole-like states, as a function of heterostructure dimension or applied electrostatic field. This is analogous to the hybridisation of states in the in-plane band structure, except that for zero in-plane wave vector there can be no appreciable hybridisation of electron and heavy hole states. A technique is described that has been developed to extract envelope functions from heterostructure wavefunctions calculated using the realistic complex band structure EPM approach. These envelope functions conform to Burt’s theory (M. G. Burt, J. Phys.: Condens. Matt. 4, 6651 (1992)) in that they are uniquely defined, continuous and smooth over all space. Comparisons with traditional effective mass envelope functions are made. The extracted envelope functions are used to demonstrate conclusively Burt's predictions (M. G. Burt, Superlatt. Mi- crostruct. 17, 335 (1995)) concerning the inadequacy of certain approximations for the calculation of interband dipole matrix elements and charge oscillation. Finally, the issue of k • p operator ordering is convincingly settled, in favour of 'ordered' over 'symmetrised' Hamiltonians, by comparison to EPM calculations, and using EPM derived k • p parameters.
72

Reparacao ossea de lesoes perirradiculares tratadas ou nao com laser em baixa intensidade (lambda = 904nm) .Estudo radiografico em humanos

SOUSA, GERDAL R. de 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:44:50Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:57:52Z (GMT). No. of bitstreams: 1 07304.pdf: 7052477 bytes, checksum: 394f524ca9aa6fd99d485926b5d230ae (MD5) / Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia) / IPEN/D-MPLO / Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo
73

Hot electron spectroscopy studies of indirect tunnel barriers

Sivaraya, Sivapathasundaram January 1999 (has links)
No description available.
74

Characterisation of intermixed quantum well material by measurements of spontaneous emission

Blay, Claire January 2000 (has links)
No description available.
75

Reparacao ossea de lesoes perirradiculares tratadas ou nao com laser em baixa intensidade (lambda = 904nm) .Estudo radiografico em humanos

SOUSA, GERDAL R. de 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:44:50Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:57:52Z (GMT). No. of bitstreams: 1 07304.pdf: 7052477 bytes, checksum: 394f524ca9aa6fd99d485926b5d230ae (MD5) / Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia) / IPEN/D-MPLO / Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo
76

Novel routes to nanodispersed semiconductors

Green, Mark A. January 1999 (has links)
No description available.
77

Near infrared cathodoluminescence of III-V heterostructures

Zanotti-Fregonara, Carlo Luigi Maria January 1998 (has links)
No description available.
78

III-V semiconducting hopping bolometers for detecting nonequilibrium phonons and astroparticles

Taele, Benedict Molibeli January 2000 (has links)
No description available.
79

Transport of two-dimensional electrons through magnetic barriers

Kubrak, Volker January 2001 (has links)
No description available.
80

Pulsed field studies of magnetotransport in semiconductor heterostructures

Dalton, Karen Sonya Helen January 1999 (has links)
No description available.

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