| 1. |
- Ekerfelt, Christina, 1957-, et al.
(författare)
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Phenotypes indicating cytolytic properties of Borrelia-specific interferon-? secreting cells in chronic Lyme neuroborreliosis
- 2003
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Ingår i: Journal of Neuroimmunology. - : Elsevier BV. - 0165-5728 .- 1872-8421. ; 145:1-2, s. 115-126
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Tidskriftsartikel (refereegranskat)abstract
- The immuno-pathogenetic mechanisms underlying chronic Lyme neuroborreliosis are mainly unknown. Human Borrelia burgdorferi (Bb) infection is associated with Bb-specific secretion of interferon-? (IFN-?), which may be important for the elimination of Bb, but this may also cause tissue injury. In order to increase the understanding of the pathogenic mechanisms in chronic neuroborreliosis, we investigated which cell types that secrete IFN-?. Blood mononuclear cells from 13 patients with neuroborreliosis and/or acrodermatitis chronicum atrophicans were stimulated with Bb antigen and the phenotypes of the induced IFN-?-secreting cells were analyzed with three different approaches. Cells expressing CD8 or TCR?d, which both have cytolytic properties, were the main phenotypes of IFN-?-secreting cells, indicating that tissue injury in chronic neuroborreliosis may be mediated by cytotoxic cells.
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| 2. |
- Forsberg, Urban, 1971-, et al.
(författare)
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Growth and characterisation 4H-SiC MESFET structures grown by Hot-Wall CVD
- 2001
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Ingår i: Proc. of the MRS 2000 Fall Meeting. ; , s. H2.3.2-
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Konferensbidrag (refereegranskat)abstract
- Metal semiconductor field effect transistor structures have been grown in a hot-wall CVD reactor. Using trimethylaluminium and nitrogen, p- and n-type epitaxial layers were grown on semi insulating substrates. A comprehensive characterization study of thickness and doping of these multi structures has been performed by using scanning electron microscopy , secondary ion mass spectrometry, capacitance-voltage and low temperature photoluminescence. Optimisation of growth parameters has resulted in very abrupt doping profiles. The grown metal semiconductor field effect transistor structures have been processed and parts of the transistor properties are presented.
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| 3. |
- Forsberg, U., et al.
(författare)
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Growth and characterisation of 4H-SiC MESFET structures grown by hot-wall CVD
- 2001
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Ingår i: Materials Research Society Symposium - Proceedings. - Boston, MA. ; , s. H2.3.1-H2.3.6
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Konferensbidrag (refereegranskat)abstract
- Metal semiconductor field effect transistor, MESFET, structures have been grown in a hot-wall CVD reactor. Using trimethylaluminium and nitrogen as dopant sources, p- and n-type epitaxial layers were grown on semi insulating substrates. A comprehensive characterization study of thickness and doping of these structures has been performed by using scanning electron microscopy, secondary ion mass spectrometry, capacitance-voltage measurements. Each technique is discussed concerning its advantage and disadvantage. Some transistor properties of MESFETs processed on the grown material are presented.
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| 6. |
- Janson, Martin S., et al.
(författare)
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Hydrogen in the wide bandgap semiconductor silicon carbide
- 2004
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Ingår i: Physica Scripta. - 0031-8949 .- 1402-4896. ; T108, s. 99-112
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we give a review of our recent results related to the incorporation of hydrogen (H) in silicon carbide (SiC) and its interaction with acceptor doping atoms and implantation induced defects. Hydrogen is an abundant impurity in the growth of epitaxial SiC since it is present in the precursor gases and since H-2 is used as the carrier gas. High concentrations of hydrogen are indeed incorporated into highly doped p-type epi-layers and it is shown that the main source is the carrier gas. Furthermore, it is revealed that the entire substrate becomes homogeneously filled with hydrogen during growth and that this hydrogen is more thermally stable than that in the epi-layer. Incorporation of hydrogen from an H-2 ambient, at temperatures considerably lower than those used for epitaxy, is also demonstrated in p-type samples coated with a catalytic metal film. This effect is most likely the cause for the increased series resistance observed in p-type SiC Schottky sensor devices using a catalytic metal gate after annealing at 600 degrees C in a H-2 containing ambient. Hydrogen is found to passivate the acceptors Al and B by forming electrically neutral H-acceptor complexes. Unlike in Si and GaAs, the two H-acceptor complexes in SiC exhibit very different dissociation energies, suggesting that the atomic configurations of the complexes are significantly different. The migration of mobile hydrogen in the presence of externally applied, or internal built-in, electric fields further reveals that hydrogen is present as H+ in p-type SiC. Finally, the redistribution and subsequent out-diffusion of low energy implanted H-1 and H-2 is investigated. Two annealing phases for the redistribution are observed, and the activation energies for the processes are extracted.
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