Influence of Resonance Tunneling on Resistivity in Semiconductors With Ionized Impurities and on Tunneling Current Between Superconductors

Abstract

AbstractThe general results for tunneling of electrons through the system barrier—well—barrier (double barrier, DB) are used to show the importance of resonance tunneling in semiconductors and superconductors. The transmission time for electrons through the double barrier, as well as the transition time between “free” states of the incoming particle and the “bound” states of the well are calculated for determining the trapping probability of electrons by ionized impurities in semiconductors. It is shown that the temperature and electric field dependence of this trapping probability has maxima, which lead to negative resistance effects due to changing the conduction electron concentration. The tunneling current between two superconductors separated by double Schottky barrier (DSB) is derived in the WKB approximation and its dependence on the applied voltage is numerically calculated for a Pb—CdS—Pb system at various temperatures. It is shown that sharp changes of the tunneling current can be detected not only at V = 2Δ (Δ energy gap of the superconductor) but also at higher voltages due to the resonance tunneling effect. These “steps” can be used for very precise measuring the temperature or magnetic field dependence of the energy gap, as well as of some parameters of the Schottky barrier.