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Laterally ordered gold nanoisland arrays made using interference lithography has been investigated in this work as SERS substrates. The developed substrates demonstrate performance in enhancing Raman signal of common dye analyte (crystal violet (CV)) comparable to commercial SERS substrates, with the lowest detectable concentration of CV ~10−6…10−7 M. They can be reused after heat treatment at 300 °C without any drop of performance. Furthermore, we found a principal difference in the effect of annealing of SERS substrates before deposition of the analyte molecules and additional in situ annealing (with molecules) on the intensity of Raman signal. Possible physical origin of the latter effect has been discussed. [ABSTRACT FROM AUTHOR]

Combined mechanical scanning probe lithography (SPL) approach applied for the direct mask-less modification of graphene oxide (GO) flakes and the mask patterns engraving in layers of chalcogenide resist with a nanometer scale resolution have been implemented in this work. It was compared the dynamics of mechanical modification of chalcogenide films and multilayer GO flakes deposited from an aqueous suspension. The double-layer As40Se60/As4Ge30S66 chalcogenide resist developed for mechanical SPL and pattern formation processes have optimized. The resist with the thickness close to 100 nm provides formation of minimal pattern elements with the size of several tens nanometers. The SPL approach was realized on the basis of serial NanoScope IIIa Dimension 3000TM scanning probe microscope, and original software utilities were developed. These mechanical SPL could be intended for the verification of innovative ideas in academic researches, the laboratory-level device prototyping, developing the functional prototypes of new devices in bio/nanosensorics, plasmonics, 2D electronics and other modern technology branches. [ABSTRACT FROM AUTHOR]

The effect of treatment in saturated acetone vapors on the spectral composition and intensity of photoluminescence (PL) in porous oblique deposited SiOx films is studied. As a result of this treatment followed by high-temperature annealing at the temperature 930 °C, considerable PL intensity growth and the small blueshift of PL peak position are observed in the porous, column-like structure films containing Si nanocrystals. A more intense shortwave band (peak position -- 540-560 nm) appears in the PL spectrum of these structures, in addition to the longwave band (760-780 nm). Both PL bands in treated samples are characterized by monomolecular radiative recombination, which can be attributed to annihilation of excitons in silicon nanocrystals embedded into oxide matrix (longwave band) and in carbon-enriched matrix near surface of oxide nanocolumns (shortwave band). The possibility to control the PL characteristics of the porous structures in a wide spectral range by above treatment is shown. [ABSTRACT FROM AUTHOR]

The effect of chemical treatment in saturated vapors of ammonia and acetone on the spectral composition and intensity of photoluminescence in porous SiO x films containing Si nanocrystals ( nc-Si) is studied. The porosity of the SiO x films is provided by oblique vacuum deposition of thermally evaporated silicon or silicon monoxide on polished silicon substrates. The kinetics of adsorption of the vapors is monitored by variations in the frequency of a quartz oscillator on which the films to be studied are deposited. As a result of chemical treatment followed by high-temperature annealing of the SiO x films at the temperature 950°C, a new band, absent from the as-prepared films, appears in the photoluminescence spectrum at shorter wavelengths. The peak position and intensity of the band depend, correspondingly, on the composition of the film and on the time duration of the treatment. It is found that the new photoluminescence band is quenched upon exposure to laser radiation at the wavelength 488 nm. The quenching is more pronounced at the band peak. The possibility of controlling the characteristics of photoluminescence of the porous structures by chemical treatment is shown. [ABSTRACT FROM AUTHOR]

Application of inorganic photoresist based on chalcogenide films for fabrication of submicrometer periodic relief on silicon wafers was investigated. For this purpose, technological process of resistive two-layer chalcogenide-Cr mask formation on a silicon surface was developed, and silicon anisotropic etching was optimized, too. This technology has been used for the fabrication of high-quality diffraction gratings on Si (100) surface with symmetric triangular and trapezium grooves and two-dimentional periodic structures. Relief parameters and diffraction properties of the obtained structures and their dependences on etching time were determined. [ABSTRACT FROM AUTHOR]

Effect of hydrogen radiofrequency plasma and chemical treatment on photoluminescence (PL) spectra of SiOx layers containing Si nanoparticles are investigated. Considerable PL intensity growth in the samples containing Si nanocrystals (nc-Si-SiOx) after plasma treatment is observed. The process saturates for time of 15 minutes. Chemical treatment in ammonia and acetone vapour before thermal annealing of SiOx layers leads to the considerable changes in PL spectra effecting both on the band shape and on the intensity. The possibility of controlled changes in PL spectra in nc-Si-SiO2 layers is shown. [ABSTRACT FROM AUTHOR]

Infrared spectroscopy and analysis of photoluminescence spectra have been used to study variations in the composition of the oxide phase in a SiOx film and the precipitation of the Si phase in the course of a rapid thermal annealing for 1–40 s at temperatures of 500–1000°C. Kinetics of phase segregation has been observed for the first time at temperatures of 600–700°C: an increase in the amount of precipitated silicon as the annealing duration increases followed by an eventual leveling off. The phase separation is brought to completion in a time as short as 1 s at temperatures higher than 900°C. The diffusion coefficient is estimated in the context of a model of the diffusion-controlled formation of Si nanoparticles. The obtained values of the diffusion coefficient exceed, by five to ten orders of magnitude, those of the silicon diffusion coefficients in SiO2 and Si and are comparable to the diffusion coefficients of the oxygen contained in these structures. It is assumed that oxygen mobility forms the basis for the mechanism of structural and phase transformations in the SiOx layers and for the formation of Si nanoparticles in the course of annealing. © 2005 Pleiades Publishing, Inc. [ABSTRACT FROM AUTHOR]