Browsing by Author "Burger, Wilfried"

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Open Access
Continuous high resolution phonon spectroscopy up to 12meV : measurement of the A+ binding energies in silicon
(1986) Burger, Wilfried; Lassmann, Kurt
We have measured the binding energies of Ga+, Al+, and In+ centers in silicon with energy-resolved phonon-induced electrical conductivity. For Ga+ and Al+ we obtain the value of about 2 meV as earlier found for B+, whereas the binding energy of In+ is 6 meV. Spectral structures attributed to impurity interactions found for higher concentrations of In at energies up to about 12 meV demonstrate that acoustic phonons up to this energy are transmitted from the tunnel junction to the substrate.
Open Access
Energy resolved measurements of the phonon ionization of D and A+ centers in silicon with superconducting Al tunnel junctions
(1984) Burger, Wilfried; Lassmann, Kurt
By means of phonon spectroscopy with superconducting-Al tunnel junctions as tunable phonon generators we show that the threshold energy of the phonon-induced conductivity for Si: B+ and Si: P- agrees well with far-infrared data, proving that the ionization is mainly a one-phonon process. This ionization mechanism allows a sensitive detection of very-high-frequency phonons.
Open Access
Phonon-induced electrical conductance in semiconductors
(1986) Lassmann, Kurt; Burger, Wilfried
The bath of thermal phonons is a well-known source of impedance to electronic conduction in solids. Turning the tables, a change in electronic conductance may be used for phonon detection, as will be discussed in the following.
Open Access
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.