Abstract

VASQUEZ, M. A.; ROMERO-PAREDES, G.  and  PENA-SIERRA, R.. Electrical transport phenomena in nanostructured porous-silicon films. Rev. mex. fis. [online]. 2018, vol.64, n.6, pp.559-565.  Epub Nov 05, 2019. ISSN 0035-001X.  https://doi.org/10.31349/revmexfis.64.559.

The charge transport mechanisms in nanostructured porous silicon (PS) films were studied through current-voltage (I-V) measurements of planar Au/PS/Au structures in dark conditions at 300 K. The films were formed by electrochemical etching of $1-5$ $\Omega$-cm p-type Si (100) wafers producing PS layers of $4.48\times {10}^9$ $\Omega$-cm. The charge transport is limited both by the space charge limited currents (SCLC) and the carrier trapping- detrapping kinetics in the inherent localized PS energy levels. I-V characteristics evolve according to the trapping-detrapping carrier kinetics in the films showing that applying external bias, the electrical current can be controlled. For the first time the trap filling limiting voltage (V${}_{\text{TFL}}$) was identified in PS films that shift between 1 and 3 volts by the carrier trapping-detrapping kinetics from the PS intrinsic defect states. An energy band diagram for the films is schematically depicted including defect states. To give a reasonable explanation of the found behavior the existence of a thin silicon oxide film covering the network-like-silicon-nanocrystallites is required, in agreement with the widely accepted PS film structural models.

Keywords : Porous silicon films; metal-insulator-metal structures; electrical characteristics; space charge limited current (SCLC); VTFL; electronic transport in interface structures; 81.07.-b; 84.37.+q; 73.40.-c; 73.40.Rw.

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