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A silicon/metal nanocomposite is fabricated by electrochemical deposition of a metal (Ni, Co, Cu) into the pores of mesoporous silicon prepared from n+-silicon consisting of highly oriented channels which are tunable in a range between 30 nm and 100 nm in their diameter and a concomitant interpore spacing. To achieve oriented pore growth with rather smooth pore walls the distance between two pores has to be smaller than twice the space charge region. The dendrites which can not be completely avoided in this mesoporous range are shorter than the pore diameter. The adjustable morphology of the porous silicon (PS) is self-assembled with a rather regular arrangement confirmed by optical diffraction of the top-view pattern. Fourier transform infrared (FTIR) measurements give details about the top surface as well as the interior surface of the pore walls. IR optical investigations are used to determine the optical parameters like the refractive index, depending on the porosity of the PS-layer. Porosities between 25% and 80% exhibit an estimated refractive index between 3 and 1.7. Different morphologies exhibit distinct IR transmittance with significant deviations of a few percent. Typical PS absorbance peaks due to Si-Hx stretching modes (2100 cm-1), O-Si-H modes (2200 cm-1) and Si-OH bending modes (1635 cm-1) are present. The channels of the obtained nanostructured semiconductor are galvanically loaded with a metal out of a metal-salt solution. The selective precipitation of metal-nanostructures is performed by pulsed deposition technique with varying electrochemical parameters depending on the deposited metal (Ni, Co, Cu). The deposition of an additional top-layer also succeeded which is important for electrical contact of the nanocomposite system. Metal loaded PS specimens show significant different transmission of variously metal-loaded samples as well as compared to bare PS. Additional absorbance peaks appear in the spectra which are due to the deposition of metal into the channels leading to a modification of the Si/SiOx/metal-interface. This obtained silicon/Ni(Co) nanoscopic system can be used for spin-injection experiments and detection of spin-polarized electrons by magneto-optical Kerr rotation. |