A generalized exponential relationship between the surface-enhanced Raman scattering (SERS) efficiency of gold/silver nanoisland arrangements and their non-dimensional interparticle distance/particle diameter ratio

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Investigation of the performance of thermally generated Au/Ag nanoislands for SERS and LSPR applications

In this work the performance of Au/Ag nanoislands was investigated for Surface Enhanced Raman Spectroscopy (SERS) and Localized Surface Plasmon Resonance (LSPR) applications. The nanoislands were generated by thermally annealing thin layers of silver and gold (having thickness in the 5-15 nm range), which were previously sputtered onto glass surfaces. Both pure (silver and gold nanoparticles – AuNP and AgNP) and composite metallic systems (silver-gold core-shell structures – Ag-Au core-shell) were evaluated based on their plasmonic and SERS sensitivity. Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) were used to measure the size, shape and distribution of the nanoparticles to correlate them with the obtained plasmonic/Raman capabilities. The technological parameters of nanoisland fabrication for optimal sensitivities are presented

Comparative analysis of SERS substrates of different morphology

In this work the surface enhanced Raman scattering (SERS) performance of gold coated patterned silicon surfaces of different morphology and period was investigated. Arrays of inverse pyramids, spheres and rounded pyramids of different sizes were fabricated by photolithography and selective etching. Thin layer of gold was sputtered onto the surface of the samples. The SERS performance of the substrates was tested using a highly dissolved organic solution

Characterisation of Channel Waveguides Fabricated in an Er3+-Doped Tellurite Glass Using Two Ion Beam Techniques

Two methods were proposed and implemented for the fabrication of channel waveguides in an Er-doped Tellurite glass. In the first method, channel waveguides were fabricated by implanting 1.5 MeV and 3.5 MeV energy N+ ions through a special silicon mask to the glass sample at various fluences. Those waveguides implanted at a fluence of 1.0 × 1016 ions/cm2 operated up to 980 nm, and showed green upconversion of the Erbium ions. In the second method, channel waveguides were directly written in the Er3+: TeO2W2O3 glass using an 11 MeV C4+ ion microbeam with fluences in the range of 1 · 1014–5 · 1016 ions/cm2. The waveguides worked in single mode regime up to the 1540 nm telecom wavelength. Propagation losses were reduced from the 14 dB/cm of the as-irradiated waveguides by stepwise thermal annealing to 1.5 dB/cm at λ = 1400 nm

Ion implantation in nanodiamonds: Size effect and energy dependence

Nanoparticles are ubiquitous in nature and are increasingly important for technology. They are subject to bombardment by ionizing radiation in a diverse range of environments. In particular, nanodiamonds represent a variety of nanoparticles of significant fundamental and applied interest. Here we present a combined experimental and computational study of the behaviour of nanodiamonds under irradiation by xenon ions. Unexpectedly, we observed a pronounced size effect on the radiation resistance of the nanodiamonds: particles larger than 8 nm behave similarly to macroscopic diamond (i.e. characterized by high radiation resistance) whereas smaller particles can be completely destroyed by a single impact from an ion in a defined energy range. This latter observation is explained by extreme heating of the nanodiamonds by the penetrating ion. The obtained results are not limited to nanodiamonds, making them of interest for several fields, putting constraints on processes for the controlled modification of nanodiamonds, on the survival of dust in astrophysical environments, and on the behaviour of actinides released from nuclear waste into the environment

LOW MISSING MASS, SINGLE- AND DOUBLE DIFFRACTION DISSOCIATION AT THE LHC

Low missing mass, single- and double diffraction dissociation is calculated for the LHC energies from a dual-Regge model. The model reproduces the rich resonance structure at low mass region, and approximate behavior for high mass-region

Origin of the asymmetric zero-phonon line shape of the silicon-vacancy center in nanocrystalline diamond films

The spectral line shape of the 1.68 eV (738 nm) emission line – usually associated with the negatively charged silicon-vacancy (SiV) center in diamond and promoted as a strong candidate for many quantum technology and nanobiology related applications – was studied by luminescence spectroscopy in di erent nanocrystalline dia- mond lms prepared by MW CVD technique. An asymmetric line pro le, expressed as a long tail on the low- energy side of the narrow luminescence band located around 1.68 eV, have been observed in all samples. By applying a multi-wavelength laser excitation, it was found that the asymmetric shape of the 1.68 eV emission line varies by changing the excitation energy and becomes more pronounced under red (1.95 eV) excitation, especially for nanodiamond lm characterized by larger average grain size. Based on the observed excitation dependent line shape behavior and on the analysis of the ne-structured emission lines, recorded by photoluminescence mapping experiments, the asymmetry of the ZPL was assigned to another optically active defect, simultaneously presented in diamond nanocrystals, namely to the GR1 center. The common presence of the GR1 and SiV centers within the CVD diamond structures even in the case of high-quality microcrystals was supported by photoluminescence excitation measurements also