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Realization of vertical and zigzag single crystalline silicon nanowire architectures

: Sivakov, V.A.; Bronstrup, G.; Pecz, B.; Berger, A.; Radnoczi, G.Z.; Krause, M.; Christiansen, S.H.


Journal of physical chemistry. C, Nanomaterials and interfaces 114 (2010), No.9, pp.3798-3803
ISSN: 1932-7447
ISSN: 1932-7455
Journal Article
Fraunhofer IWM ()

Silicon nanowire (SiNW) ensembles, with vertical and zigzag architectures have been realized using wet chemical etching of bulk silicon wafers (p-Si(l 11) and p-Si(100)) with it mask of silver nanoparticles that are deposited by wet electroless deposition. The etching of SiNWs is based oil Subsequent treatments in chemical Solutions Such is 0.02 M aqueous Solutions of silver nitrate (AgNO3) followed by 5 M hydrofluoric acid and 30% hydrogen peroxide (H2O2). The etching of the Si wafers is mediated by the reduction of silver oil the Silicon Surface and in parallel by the oxidation of Si thereby forming SiO2 which is dissolved ill the HF Surroundings. The morphology of the starting silver (Ag) layer/Ag nanoparticles that form during processing oil the Si wafer surfaces strongly influences the morphology of the SiNW ensembles and homogeneity of the etch profile. Our observations Suggest that the Ag layer/Ag nanoparticles not only catalyze the wet chemical etching of silicon but also strongly catalyze the decomposition of H2O2 so that the temperature of the etching Solution substantially increases (strong exothermic reaction) and thus the etching velocity of bulk material. The morphology and microstructure of single crystalline SiNWs with respect to their crystallographic orientation was investigated by scanning (SEM) and transmission electron (TEM) microscopies and by electron backscatter diffraction (EBSD) in ill SEM. Straight SiNWs Lis well as zigzag SiNWs can be realized depending oil processing peculiarities. The optical characteristics such as absorption, transmission, and reflectance of the different silicon 1D architectures were investigated in an integrating sphere. Strong absorption and less reflection of visible and near-infrared light by the SiNW ensembles Suggest that Such material call he applied in the fields of opto-electronics, photonics and photovoltaics.