Carrier transport and related phenomena in nanosize periodic silicon/insulator structures

Experimental facts and theoretical models describing mechanisms of carrier transport across silicon/insulator quantum wells are reviewed. Single and multi quantum wells (MQW) formed in periodic Si/CaF2 and Si/SiO2 nanostructures are mainly covered. Carrier traps in the barrier material (CaF2, SiO2) are shown to have dramatic influence on electron and hole tunneling through the barriers. When the carrier energy coincides with local trap levels, the carrier transport gets the resonant character, otherwise the effects caused by charging of the traps dominate. As a result, a region of negative differential resistance (NDR) and memory (hysteresis) effect become typical for I–V curves of the structures. Intensity of electroluminescence is shown to be mediated by the competition between radiative recombination and non-radiative Auger processes in the wells. Novel applications of periodic quantum well nanostructures are considered.