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  • 1
    Electronic Resource
    Electronic Resource
    Defect-level analysis of semiconductors by a new differential evaluation ofn(1/T)-characteristics (1979)
    Springer
    Applied physics 19 (1979), S. 307-312 
    Details
    ISSN: 1432-0630
    Keywords: 71.20 ; 71.55 ; 72.80
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A new method for the defect-level analysis of extrinsic semiconductors is described. Provided that the defect-level concentration is not too large and the temperature is not too low, the Fermi levelE F is shifted with increasing temperature from a position near the conduction (or valence) band towards the middle of the forbidden gap monotonously. Thus majority carriers are emitted into the conduction (or valence) band from the defect levels successively. If for a small increment of the temperature the Fermi levelE F is shifted by ΔE F and the concentration of free majority carriers is increased by Δn, then the ratio Δn/ΔE F is a measure of the defect-level concentration within ΔE F . Furthermore we discuss how this analysis is influenced by additional defect levels outside the range over which the Fermi energy can be shifted by variation of the temperature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00900474
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  • 2
    Electronic Resource
    Electronic Resource
    On the density of localized levels in amorphous silicon (1979)
    Springer
    Applied physics 18 (1979), S. 427-429 
    Details
    ISSN: 1432-0630
    Keywords: 71.20 ; 71.55 ; 72.80
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The distribution of the localized levelsg(ε) in the forbidden gap of amorphous silicon is calculated from the dependence of the Fermi energy on the doping concentration of phosphorus donors and boron acceptors. The minimum ofg(ε) is verified by this method to be in the order of 1017 to 1018 cm−3eV−1, whereas the maxima ofg(ε), which have been reported in the literature, are not confirmed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00899699
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Regulation of plant genes specifically induced in nitrogen-fixing nodules: role of cis-acting elements and trans-acting factors in leghemoglobin gene expression (1989)
    Springer
    Plant molecular biology 13 (1989), S. 319-325 
    Details
    ISSN: 1573-5028
    Keywords: nodulins ; leghmoglobin ; gene regulation ; cis-acting elements ; trans-acting factors ; transgenic plants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transgenic alfalfa plants harboring a gene fusion between the soybean leghemoglobin (lbc3) promoter region and the chloramphenicol acetyl transferase (cat) gene were used to determine the influence of rhizobial mutants on lb gene expression in nodules. The promoter region of the Sesbania rostrata glb3 (Srglb3) leghemoglobin gene was examined for the presence of conserved motifs homologous to binding site 1 and 2 of the soybean lbc3 promoter region, found to interact with a trans-acting factor present in soybean nodule nuclear extracts (Jensen EO, Marcker KA, Schell J, de Bruijn FJ, EMBO J 7: 1265–1271, 1988). Subfragments of the S. rostrata glb3 (Srglb3) promoter region were examined for binding to trans-acting factors from nodule nuclear extracts. In addition to the binding sites previously identified (Metz BA, Welters P, Hoffmann HJ, Jensen EO, Schell J, de Bruijn FJ, Mol Gen Genet 214: 181–191), several other sites were found to interact with trans-acting factors. In most cases the same trans-acting factor(s) were shown to be involved. One fragment (202) was found to bind specifically to a different factor (protein) which was extremely heat-resistant (100°C). The appearance of this factor was shown to be developmentally regulated since the expected protein-DNA complexes were first observed around 12 days after infection, concomitant with the production of leghemoglobin proteins. Fragments of the Srglb3 5′ upstream region were fused to the β-glucuronidase reporter gene with its own CAAT and TATA box region or those of the cauliflower mosaic virus 35S and nopaline synthase (nos) promoters. These constructs were used to generate transgenic Lotus corniculatus plants and their expression was measured in different plant tissues. The Srglb3 CAAT and TATA box region was found to be required for nodule-specific expression and several upstream enhancer-type regions were identified.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00025320
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    Paper (German National Licenses)
    Fulltext
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