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 result in the formation of an anisotropic material with strings of nanometersized silicon granules embedded in insulating silicon dioxide SiO₂. In this range of granule sizes the correlation effects in the tunneling of electrons (holes) are strong on account of their Coulomb interaction. 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 with a PS interlayer on p ⁺-Si, which exhibit current steps on the forward and reverse branches, are presented. The current steps are attributed to discrete hole tunneling along the silicon strings in SiO₂. Pis’ma Zh. éksp. Teor. Fiz. 67, No. 10, 794–797 (25 May 1998)