Hamburg 2001 – scientific programme
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HL: Halbleiterphysik
HL 28: Si / Ge
HL 28.1: Talk
Thursday, March 29, 2001, 10:30–10:45, S9/10
Free charge carrirs in mesoporous silicon — •Victor Yu. Timoshenko1,2, Thomas Dittrich1, Vladimir Lysenko3, Maxim G. Lisachenko2, and Frederick Koch1 — 1Technische Universitaet Muenchen, Physik Department E16, D-85748 Garching, Germany — 2M. V. Lomonosov Moscow State University, Faculty of Physics, 119899 Moscow, Russia — 3INSA de Lyon, LPM, 20 av. Albert Einstein, Bat. 502, 69621 Villeurbanne Cedex, France
Free charge carriers are observed by infrared absorption in free standing mesoporous Si (meso-PS) despite the small dimensions of the Si nanowires (diameters 6-10 nm) in this material. Adsorption of acceptor molecules or filling the pores with dielectric liquids are used to increase the concentration of free holes (p) up to the half of the doping level of the heavily boron doped substrate from which the meso-PS is made. Considering the value of p and the dc electrical conductivity, the hole mobility is determined. The model of dielectric confinement for charge carriers and hydrogenic impurities is applied to explain the dependence of p and the mobility on the dielectric constant of the ambience of the Si nanowires.