222 research outputs found

    Electroabsorption spectroscopy of amorphous Si/SiC quantum well structures

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    Copyright 1989 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters, 55(8), 763-765, 1989 and may be found at http://dx.doi.org/10.1063/1.10179

    Optical observation of subbands in amorphous silicon ultrathin single layers

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    Copyright 1988 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters, 53(22), 2170-2172, 1987 and may be found at http://dx.doi.org/10.1063/1.10027

    Carrier transport property in the amorphous silicon/amorphous silicon carbide multilayer studied by the transient grating technique

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    Copyright 1987 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters, 51(16), 1259-1261, 1987 and may be found at http://dx.doi.org/10.1063/1.9869

    Electroreflectance spectroscopy in self-assembled quantum dots: lens symmetry

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    Modulated electroreflectance spectroscopy ΔR/R\Delta R/R of semiconductor self-assembled quantum dots is investigated. The structure is modeled as dots with lens shape geometry and circular cross section. A microscopic description of the electroreflectance spectrum and optical response in terms of an external electric field (F{\bf F}) and lens geometry have been considered. The field and lens symmetry dependence of all experimental parameters involved in the ΔR/R\Delta R/R spectrum have been considered. Using the effective mass formalism the energies and the electronic states as a function of F{\bf F} and dot parameters are calculated. Also, in the framework of the strongly confined regime general expressions for the excitonic binding energies are reported. Optical selection rules are derived in the cases of the light wave vector perpendicular and parallel to % {\bf F}. Detailed calculation of the Seraphin coefficients and electroreflectance spectrum are performed for the InAs and CdSe nanostructures. Calculations show good agreement with measurements recently performed on CdSe/ZnSe when statistical distribution on size is considered, explaining the main observed characteristic in the electroreflectance spectra

    Squamous cell carcinoma (Marjolin's ulcer) in an orocutaneous fistula of a large mandibular ameloblastoma: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Ameloblastomas are rare lesions constituting 1% of all jaw tumors. Oral squamous cell carcinomas are common lesions; these constitute about 90% of all oral cancers. Concurrent tumors consisting of ameloblastoma and squamous cell carcinoma are extremely rare.</p> <p>Case presentation</p> <p>This case report describes a 35-year-old African man who presented with a large mandibular tumor with an orocutaneous fistula that was found to be an ameloblastoma on histopathological examination, with concurrent squamous cell carcinoma histology within the fistula. This presentation was consistent with a Marjolin's ulcer within an ameloblastoma.</p> <p>Conclusion</p> <p>Ameloblastomas and Marjolin's ulcers require different management strategies. Careful histopathological examination of surgical specimens is key to patient outcome, as treatment of these patients depends on an accurate diagnosis.</p

    Exchange Anisotropy in Epitaxial and Polycrystalline NiO/NiFe Bilayers

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    (001) oriented NiO/NiFe bilayers were grown on single crystal MgO (001) substrates by ion beam sputtering in order to determine the effect that the crystalline orientation of the NiO antiferromagnetic layer has on the magnetization curve of the NiFe ferromagnetic layer. Simple models predict no exchange anisotropy for the (001)-oriented surface, which in its bulk termination is magnetically compensated. Nonetheless exchange anisotropy is present in the epitaxial films, although it is approximately half as large as in polycrystalline films that were grown simultaneously. Experiments show that differences in exchange field and coercivity between polycrystalline and epitaxial NiFe/NiO bilayers couples arise due to variations in induced surface anisotropy and not from differences in the degree of compensation of the terminating NiO plane. Implications of these observations for models of induced exchange anisotropy in NiO/NiFe bilayer couples will be discussed.Comment: 23 pages in RevTex format, submitted to Phys Rev B
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