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Publication Type: search.filters.UBSTyp.KonferenzbeitragSubject: search.filters.subject.530Author: search.filters.author.Lassmann, KurtInstitute: search.filters.UBSInstitut.Sonstige Einrichtung

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Now showing 1 - 4 of 4
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    Influence of defects on the splitting of the acceptor ground state in silicon
    (1984) Ambrosy, Anton; Lassmann, Kurt; Goer, Anne M. de; Salce, Bernard; Zeile, Heinrich
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    Resonance and relaxation attenuation by neutral acceptors in a magnetic field
    (1977) Schad, Hanspeter; Lassmann, Kurt; Zeile, Heinrich
    Fine structure, level splitting, and relaxation times of the acceptor ground state in cubic semiconductors can be deduced from ultrasonic attenuation. By the application of a magnetic field it is possible to vary the coupling strength and the number of acceptors on speaking terms with the ultrasonic wave. Making use of this possibility, we have determined directly effective coupling constants for relaxation attenuation and the temperature dependence of the critical intensity for saturation of the resonant interaction. Results obtained for p-type GaAs and Si are discussed in comparison with analogous results for glasses.
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    Shallow traps correlated with deep impurities in silicon as obtained by phonon induced conductance
    (1986) Burger, Wilfried; Lassmann, Kurt; Holm, Claus; Wagner, Peter
    At low temperatures shallow neutral donors and acceptors in silicon can bind an extra carrier to form the so-called D- and A+ centers. With the method of phonon-induced electrical conductivity (PIC) we find the same threshold energies for the detachment of these carriers associated with the shallow impurities P and B, as have been obtained previously by FIR measurements. This shows that the detachment is by a one-phonon process. We find that there is no central cell correction for the binding to the deeper acceptors Al and Ga, whereas for In+ the binding energy is as large as 5,8 meV. We interprete this dependence on acceptor species as another example of the shallow-deep instability of the binding energy with the variation of the central cell potential.
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    Phonon scattering due to deep acceptors in semiconductors
    (1976) Combarieu, Andre de; Lassmann, Kurt
    We have measured the magnetothermal conductivity in GaAs(Mn) and Si(In) for temperatures between 1.4 K and 90 K at magnetic fields up to 8 T. In both cases the dopants are deep acceptors with binding energy much larger (110 meV and 165 meV respectively) than given by the effective mass theory (~ 35 meV). There is a double interest in such systems: First, an excited level 3 meV (4.2 meV) above the acceptor ground state has been concluded from ultrasonic measurements. Such an excited state might be connected with a Jahn-Teller effect of these deeper acceptors and should be seen by resonant phonon scattering in thermal conductivity. Second, an anomalous behavior of the magnetothermal conductivity has been found for shallowacceptors in Ge (but not in Si) making comparison with systems with different g-factors desirable. The g-factors of acceptors in GaAs are roughly three times, the g-factor of Si(In) about 0.6 times that of Si(B).