DISCRETE TUNNELING OF HOLES IN POROUS SILICON

It is pointed out that in the partial oxidation of porous silicon (PS) formed on heavily doped crystals, the topology of the pores can resul t in the formation of an anisotropic material with strings of nanomete r-sized silicon granules embedded in insulating silicon dioxide SiO2. In this range of granule sizes the correlation effects in the tunnelin g of electrons (holes) are strong on account of their Coulomb interact ion. This should be manifested as discrete electron and hole tunneling at temperatures comparable to room temperature. The room-temperature current-voltage characteristics of n(+)-PSp(+)-p(+) diode structures w ith a PS interlayer on p(+)-Si, which exhibit current steps on the for ward and reverse branches, are presented. The current steps are attrib uted to discrete hole tunneling along the silicon strings in SiO2. (C) 1998 American Institute of Physics. [S0021-3640(98)01510-2].