Synthesis and catalytic activity of hybrid metal/silicon nanocomposites (2008)
Polisski, S., Goller, B., Lapkin, Alexei, Fairclough, S., Kovalev, D.
In this Letter we demonstrate that hydrogen-terminated porous silicon (PSi) layers and powders can serve as highly efficient reductive templates for noble metal salts. The reduction results in metal...
Photo-oxidation by singlet oxygen generated on nanoporous silicon in a LED-powered reactor (2008)
Lapkin, Alexei, Boddu, V. M., Aliev, G. N., Goller, B., Polisski, S., Kovalev, D.
An annular flow photochemical reactor illuminated by UV and green (524 nm) light emitting diodes (LEDs) was characterised by a chemical actinometer. Very high efficiency of absorption of photons,...
Scaleable synthesis route for silicon nanocrystal assemblies (2007)
Limaye, S., Subramanian, S., Goller, B., Diener, J., Kovalev, D.
Spin-flip excitation of molecules mediated by photoexcited silicon nanocrystals (2007)
Goller, B., Polisski, S., Kovalev, D.
Spin-flip excitation of molecules by photons is forbidden in the dipole approximation. Usually it requires the presence of a light-absorbing donor which subsequently transfers energy of electronic...
Photosensitization of oxygen molecules by surface-modified hydrophilic porous Si (2007)
Fujii, M., Nishimura, N., Fumon, H., Hayashi, S., Akamatsu, K., Tsuruoka, T., ...
Silicon nanocrystals as photosensitizers of active oxygen for biomedical applications (2006)
Timoshenko, V. Y., Kudryavtsev, A. A., Osminkina, L. A., Vorontsov, A. S., Ryabchikov, Y. V., Belogorokhov, I. A., ...
Dynamics of photosensitized formation of singlet oxygen by porous silicon in aqueous solution (2006)
Fujii, M., Nishimura, N., Fumon, H., Hayashi, S., Kovalev, D., Goller, B., ...
Timoshenko, V.Y., Shalygina, O.A., Lisachenko, M.G., Zhigunov, D.M., Teterukovk, S.A., Kashkarov, P., ...
Timoshenko, V. Y., Shalygina, O. A., Lisachenko, M. G., Zhigunov, D. M., Teterukov, S. A., Kashkarov, P. K., ...
The photoluminescence (PL) spectra and kinetics of erbium-doped layers of silicon nanocrystals dispersed in a silicon dioxide matrix (nc-Si/SiO2) are studied. It was found that optical excitation of...
Form birefringence of anisotropically nanostructured silicon (2005)
Kunzner, N., Diener, J., Gross, E., Kovalev, D., Timoshenko, V. Y., Fujii, M.
We present a detailed study of the anisotropic optical properties of mesoporous silicon layers prepared from substrates having different doping levels under various preparation conditions. We...
Silicon nanocrystals: Photosensitizers for oxygen molecules (2005)
Molecular oxygen plays an important role in many of the chemical reactions involved in the synthesis of biological life. In this review, we explore the interaction between O-2 and silicon...
Singlet oxygen formation by porous Si in solution (2005)
Fujii, M., Usui, M., Hayashi, S., Gross, E., Kovalev, D., Kunzner, N., ...
Singlet oxygen formation by porous Si in solution has been demonstrated. It has been shown that the absorption band of 1,3-diphenylisobenzofuran (DPBF) in benzene becomes smaller, i.e., DPBF is...
Fujii, M., Kovalev, D., Goller, B., Minobe, S., Hayashi, S., Timoshenko, V. Y.
The formation of singlet oxygen due to the energy transfer from excitons confined in silicon nanocrystals to oxygen molecules is studied using time-resolved photoluminescence spectroscopy. The...
Diener, J., Kunzner, N., Gross, E., Kovalev, D., Fujii, M.
Anisotropic nanostructuring of bulk silicon (Si) wafers leads to a significant in-plane optical anisotropy of single porous silicon (PSi) layers. Additionally a variation of the etching current in...
Highly explosive nanosilicon-based composite materials (2005)
Clement, D., Diener, J., Gross, E., Kunzner, N., Timoshenko, V. Y., Kovalev, D.
We present a highly explosive binary system based on porous silicon layers with their pores filled with solid oxidizers. The porous layers are produced by a standard electrochemical etching process...
Capillary condensation in linear mesopores of different shape (2004)
Wallacher, D., Kunzner, N., Kovalev, D., Knorr, N., Knorr, K.
Timoshenko, V.Y., Slalygina, O.A., Lisaschenko, M.G., Kashkarov, P.K., Kovalev, D., Heitmann, J., ...
Excitons in Si nanocrystals: Confinement and migration effects (2004)
Heitmann, J., Müller, F., Yi, L., Zacharias, M., Kovalev, D., Eichhorn, F.
Capillary condensation in linear mesopores of different shape (2004)
Wallacher, D., Kunzner, N., Kovalev, D., Knorr, N., Knorr, K.
The hysteresis and kinetics of capillary condensation of N-2 and Ar in linear mesopores, produced by etching of Si wafers, have been studied for different pore shapes, including the ink bottle...
Photodegradation of porous silicon induced by photogenerated singlet oxygen molecules (2004)
Kovalev, D., Gross, E., Diener, J., Timoshenko, V. Y., Fujii, M.
We report on the mechanism of photodegradation of porous silicon luminescence in ambient containing molecular oxygen. Energy transfer from excitons confined in silicon nanocrystallites to molecular...
Excitons in Si nanocrystals: Confinement and migration effects (2004)
Heitmann, J., Muller, F., Yi, L. X., Zacharias, M., Kovalev, D., Eichhorn, F.
A detailed analysis of the strong room-temperature photoluminescence (PL) signal of size controlled nc-Si is reported. The size control of nc-Si is realized by evaporation of SiO/SiO2 superlattices...
Fujii, M., Usui, M., Hayashi, S., Gross, E., Kovalev, D., Kunzner, N., ...
Formation of singlet oxygen in solution by using Si nanocrystals as photosensitizers has been demonstrated. It has been shown that the absorption band of 1,3-diphenylisobenzofuran (DPBF) in benzene...
Fujii, M., Minobe, S., Usui, M., Hayashi, S., Gross, E., Diener, J., ...
Photoluminescence (PL) from singlet oxygen generated by energy transfer from porous Si is observed at room temperature in an organic solvent. The evidence of the indirect excitation by energy...
Planar silicon-based light polarizers (2004)
Diener, J., Kunzer, N., Gross, E., Kovalev, D., Fujii, M.
Silicon-based thin-film polarizers operating in the visible and near-infraed spectral range are fabricated by electrochemical etching of bulk silicon wafers. Anisotropically etched (110) porous...
Polarized optical gain and polarization-narrowing of heavily oxidized porous silicon (2004)
Cazzanelli, M., Kovalev, D., Dal Negro, L., Gaburro, Z., Pavesi, L.
We report on a polarization-sensitive optical gain in a blue-emitting Si/SiO2 nanocrystalline system having a high degree of emission polarization memory. This system can show a positive optical gain...
Anisotropy of optical absorption in birefringent porous silicon (2003)
Timoshenko, V. Y., Osminkina, L. A., Efimova, A. I., Golovan, L. A., Kashkarov, P. K., Kovalev, D., ...
Strong polarization-sensitive anisotropy of the optical absorption in the visible and infrared spectral range is observed in porous silicon (PSi) layers formed from bulk (110) Si wafers. It is shown...
Capillary condensation monitored in birefringent porous silicon layers (2003)
Kunzner, N., Gross, E., Diener, J., Kovalev, D., Timoshenko, V. Y., Wallacher, D.
We performed studies on the capillary condensation of various substances in optically anisotropic porous silicon layers. Their strong in-plane form birefringence has been utilized to analyze the...
Efficient light scattering by a liquid network confined in a porous matrix (2003)
Gross, E., Kovalev, D., Kunzner, N., Diener, J., Polisski, G., Koch, F., ...
We report on a system exhibiting extremely efficient light scattering properties: a liquid network formed by capillary condensation in a porous matrix. We find that the scattering efficiency depends...
Gross, E., Kovalev, D., Kunzner, N., Diener, J., Koch, F., Timoshenko, V. Y., ...
We report on a spectroscopic study of electronic energy transfer from excitons confined in silicon nanocrystals to triplet ground-state oxygen molecules, being either physisorbed on the nanocrystal...
Diener, J., Kunzner, N., Kovalev, D., Gross, E., Koch, F., Fujii, M.
Electro-chemical etching of heavily doped, (110) oriented, p(+) (boron) doped silicon wafers results in porous silicon (PSi) layers which exhibit a strong in-plane anisotropy of the refractive index...
Birefringent Nanostructured Silicon: New Promising Material for Linear and Nonlinear Optics (2002)
Kovalev, D., Timoshenko, V. Yu., Golovan, L., Kuenzner, N.
Porous Si layers produced by anisotropic electrochemical etching of bulk Si exhibit strong in-plane birefringence which depends on the sizes of Si nanocrystals spacing between them and dielectric...
Efficient Photoluminescence Upconversion in Porous Si (2002)
Kuenzer, N., Diener, J., Kovalev, D., Polisski, G., Koch, F.
We report on a new phenomenon specific for a system of spatially interconnected nanocrystal assemblies: efficient low temperature photoluminescence (PL) conversion at resonant optical excitation of...
Strongly opalescent liquid network formed in a porous silicon matrix (2002)
Kovalev, D., Gross, E., Kunzner, N., Polisski, G., Koch, F., Timoshenko, V. Y., ...
We report on a medium exhibiting extremely efficient light scattering properties: a liquid network formed in a porous silicon matrix. We find that the scattering efficiency depends strongly on the...
Kovalev, D., Gross, E., Kunzner, N., Koch, F., Timoshenko, V. Y., Fujii, M.
We demonstrate efficient resonant energy transfer from excitons confined in silicon nanocrystals to molecular oxygen (MO). Quenching of photoluminescence (PL) of silicon nanocrystals by MO...
Stimulated light emission in dense fog confined inside a porous glass matrix (2002)
Gross, E., Kovalev, D., Kunzner, N., Diener, J., Koch, F., Fujii, M.
We report on light amplification through stimulated emission in a dielectrically disordered medium. Liquid fragments confined in the solid matrix of porous quartz layers result in a random...
Dichroic behavior of multilayer structures based on anisotropically nanostructured silicon (2002)
Diener, J., Kunzner, N., Kovalev, D., Gross, E., Koch, F., Fujii, M.
Multilayer structures of anisotropically nanostructured (birefringent) silicon have been fabricated and studied by polarization-resolved reflection and transmission measurements. We demonstrate that...
Resonant tunneling in partially disordered silicon nanostructures (2001)
Tsybeskov, L., Grom, G. F., Krishnan, R., Montes, L., Fauchet, P. M., Kovalev, D., ...
Low-temperature vertical carrier transport in layered structures comprised of Si nanocrystals separated in the growth direction by angstrom-thick SiO2 layers exhibits entirely unexpected,...
Efficient photoluminescence upconversion in porous Si (2001)
Kunzner, N., Kovalev, D., Heckler, H., Diener, J., Polisski, G., Koch, F., ...
We report on a new phenomenon specific for a system of spatially interconnected nanocrystal assemblies: efficient low temperature photoluminescence (PL) upconversion at resonant optical excitation of...
Giant birefringence in anisotropically nanostructured silicon (2001)
Kunzner, N., Kovalev, D., Diener, J., Gross, E., Timoshenko, V. Y., Polisski, G., ...
We performed a study of the in-plane birefringence of anisotropically nanostructured Si layers, which exhibit a greater difference in the main value of the anisotropic refractive index than that of...
Kovalev, D., Timoshenko, V. Y., Kunzner, N., Gross, E., Koch, F.
We report new types of heterogeneous hydrogen-oxygen and silicon-oxygen branched chain reactions which have been found to proceed explosively after the filling of pores of hydrogen-terminated porous...
Strong in-plane birefringence of spatially nanostructured silicon (2001)
Kovalev, D., Polisski, G., Diener, J., Heckler, H., Kunzner, N., Timoshenko, V. Y., ...
We report on a strong intrinsic optical anisotropy of Si induced by its dielectric patterning. As a result, an in-plane birefringence for nanostructured (110) Si surfaces is found to be 10(4) times...
Optical properties of silicon nanocrystals (2001)
Kovalev, D., Heckler, H., Polisski, G., Diener, J., Koch, F.
The purpose of the paper is to survey the experimental work which has been carried out towards detailed understanding of the basic optical properties of silicon nanocrystals. We would like to...
Highly sensitive recognition element based on birefringent porous silicon layers (2001)
Gross, E., Kovalev, D., Kunzner, N., Timoshenko, V. Y., Diener, J., Koch, F.
Anisotropically nanostructured silicon layers exhibit a strong in-plane birefringence. Their optical anisotropy parameters are found to be extremely sensitive to the presence of dielectric substances...
Phase matching of second-harmonic generation in birefringent porous silicon (2001)
Golovan, L. A., Timoshenko, V. Y., Fedotov, A. B., Kuznetsova, L. P., Sidorov-Biryukov, D. A., Kashkarov, P. K., ...
Optical second-harmonic generation is investigated in free-standing (110) porous silicon films having strong inplane birefringence. Based on the measured values of the refractive indices, the...
Dichroic Bragg reflectors based on birefringent porous silicon (2001)
Diener, J., Kunzner, N., Kovalev, D., Gross, E., Timoshenko, V. Y., Polisski, G., ...
Multilayers of anisotropically nanostructured silicon (Si) have been fabricated and studied by polarization-resolved reflection measurements. Alternating layers having different refractive indices...
Morphology of porous silicon layers deduced from polarization memory experiments (2001)
Diener, J., Kovalev, D., Polisski, G., Kunzner, N., Koch, F.
The morphology of porous silicon layers has been investigated by polarization resolved photoluminescence measurements in different geometrical arrangements. A uniaxial alignment of the long...
Luminescence properties of two-photon excited silicon nanocrystals (2001)
Diener, J., Kovalev, D., Polisski, G., Koch, F.
Visible photoluminescence (PL) from silicon nanocrystals (NCs) in porous silicon (PSi) at two-photon excitation (two-photon absorption) has been studied. For resonant excitation at low temperatures...
Resonant excitation of interfacial Si-O: possibility of nonthermal processing (2001)
Diener, J., Kovalev, D., Koch, F.
Studying the heating of oxidized porous Si excited by IR-pulses from a CO2 laser we observe a time delay of a fraction of a gs for some infrared frequencies. For 1030 cm(-1) the transfer of energy is...
Strong low-temperature anti-Stokes photoluminescence from coupled silicon nanocrystals (2001)
Diener, J., Kovalev, D., Heckler, H., Polisski, G., Kunzner, N., Koch, F., ...
We report efficient low-temperature anti-Stokes photoluminescence (upconverted photoluminescence= UPL) at resonant excitation of coupled silicon nanocrystals (NCs) in porous silicon (PSi). This...
Exciton states of silicon nanocrystals studied by magneto-optical spectral hole burning (2001)
Diener, J., Kovalev, D., Heckler, H., Polisski, C., Koch, F.
The absorbing and emitting states of excitons, confined in silicon nanocrystals, are separately investigated by magneto-optical spectral hole burning. Due to Zeeman splitting of the exciton ground...
The recombination statistic of the visible photoluminescence of Si nanocrystalls (1997)
Diener, J., Kovalev, D., Ben-Chorin, M., Ganichev, Sergey, Polisski, G., Koch, F.
Excitation of the porous silicon photoluminescence by a multiphoton vibronic process (1996)
Diener, J., Ben-Chorin, M., Kovalev, D., Ganichev, Sergey, Koch, F.
We study the emission of photons from porous Si after high-level vibrational excitation in the Si---O absorption band using a pulsed CO2 laser. Narrow resonances in the efficiency of light generation...
The recombination statistic of the visible photoluminescence of Si nanocrystalls (1996)
Diener, J., Kovalev, D., Ben-Chorin, M., Ganichev, Sergey, Polisski, G., Koch, F.
Luminescence from highly excited vibronic states in porous silicon (1996)
Diener, J., Ben-Chorin, M., Kovalev, D., Ganichev, Sergey, Koch, F.
Light from Porous Silicon by Multiphoton Vibronic Excitation (1995)
Diener, J., Ben-Chorin, M., Kovalev, D., Ganichev, Sergey, Koch, F.
We study the emission of photons from porous Si after high-level vibrational excitation in the Si-O absorption band using a pulsed CO2 laser. Narrow resonances in the efficiency of light generation...