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HL: Halbleiterphysik

HL 28: Si / Ge

HL 28.1: Vortrag

Donnerstag, 29. März 2001, 10:30–10:45, S9/10

Free charge carrirs in mesoporous silicon — •Victor Yu. Timoshenko^1,2, 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.