Seminar of International Laboratory of High Magnetic Fields and Low Temperatures PAS
ul. Gajowicka 95, sala seminaryjna (nowy budynek, II piętro)
Effect of magnetic field on low-temperature conductivity in silicon p-n junction (Yu. M. Shvarts, A. B. Aleynikov, and V. A. Berezovets)
dr Yu. M. Shvarts
V. E. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, Kiev, Ukraine
Effect of magnetic field (up to 14 Т) on current-voltage characteristics of silicon n+-p diode with doping level of the diode base (by boron) which is somewhat less than it is necessary for insulator-metal transition has been investigated. Planar design of the diode has made it possible to separate an influence of magnetic field on mobility of carriers executing impact ionization of the acceptor impurity and on the ionization energy itself. This has permitted determination of dependence of the ionization energy on magnetic field induction B. Quantitative agreement with existing simplified theories is absent but obtained result (by means of analysis of experimental data) manifests commonly observed in other semiconductors the dependence B1/3- type. Magnetoresistance of the diode which (owing to heavy doping of the diode emitter) is, in essence, magnetoresistance of the diode freezed-out base is constructed by the experimental current-voltage characteristics. It demonstrates a hopping character of silicon conduction both in pre-breakdown and in post-breakdown regimes. In the first case the conduction takes place in the impurity band and in the second one – in the tail of the density of states of the valence band.
