Low energy Ag ions were implanted into silicon and annealed at different temperatures in order to generate plasmonic active silicon hybrids. It was found that as the ion fluence of irradiation was increased, a monotonic decrease in the absorption spectra in the ultraviolet region occurs, due to amorphization and macrostructuring of the Si surface. At the same time, the optical spectra are characterized by a strong band after implantation presenting the contribution of the surface plasmon resonance (SPR) of Ag nanoparticles. After heat treatment at 500 and 600?C, the SPR peak shifts to lower wavelengths, as compared to as implanted samples, whereas the plasmon position shifts to higher wavelengths for annealing at 700?C. This observation can be explained by either an out-diffusion of Ag or by stress relaxation and recrystallization of silicon.

Abstract We investigated the structural and optical changes of Si (100) induced by single or multiple low energy silver ion irradiation with fluences up to 1016 ions/cm2. The irradiated samples were analyzed by the means of Rutherford backscattering spectrometry, X-ray photoelectron spectroscopy, transmission electron microscopy and spectroscopic ellipsometry measurements. The results revealed that after 60, 75 and multiple (75 + 60) keV ion implantation Ag atoms are preferentially situated in the near-surface region of the Si with the maximum distribution at 20, 26 and 42 nm, respectively. Spherical-like particles with diameters below 5 nm are homogenously distributed along the ion track of implanted ions. In the case of single ions implantations the Ag nanoparticles are distributed in the shallower regions of silicon, while subsequent implantation of silver with multiple ion energies results in a distribution in a wider region and again a shift of the Ag nanoparticles to larger depths of silicon substrate. As the ion fluence increases a monotonic decrease in the absorption in the ultraviolet region of the spectrum was observed, due to amorphization of the silicon. On the other hand, for the fluences in the range of 1014–1015 ions/cm2 in the long-wave regions wide absorption band appears at wavelengths between 700 nm and 1000 nm, which is due to plasmon resonance of Ag nanoparticles synthesized during implantation. The position of the resonance peak reflects not only the change in the ion fluence, but also the difference in the incident Ag ion energy. After implantation to the higher ion fluences of 1016 ions/cm2 this absorption band was shifted over 1000 nm, which is much above the known values for plasmon resonances of Ag nanoparticles.

Abstract Nanosphere lithography is an effective technique for high throughput fabrication of well-ordered patterns on large areas. This study reports on nanostructuring of silicon samples by means of Ag ions implantation through self-organized polystyrene (PS) masks. The PS nanospheres with a diameter of ∼150 nm were self-assembled in a hexagonal array on top of Si(100) wafers, and then used as a mask for subsequent 60 keV silver ion implantation. Different fluences were applied up to 2 × 1016 ions/cm2 in order to create a distribution of different sizes and densities of buried metal nanoparticles. The surface morphology and the subsurface structures were studied by scanning electron microscopy and cross-sectional transmission electron microscopy, as a function of the mask deformation upon irradiation and the implantation parameters itself. We demonstrate that Ag is implanted into Si only through the mask openings, thus forming a regular array of amorphized regions over the wide area of silicon substrate. These fragments are of similar dimensions of the spheres with widths of about 190 nm and distributed over 60 nm in depth due to the given ion range. At the subsurface region of the implanted fragments, the synthesis of small sized and optically active Ag nanoparticles is clearly observed. The samples show a strong absorption peak in the long-wavelength region from 689 to 745 nm characteristic for surface plasmon resonance excitations, which could be fitted well using the Maxwell-Garnett`s theory.

This study deals with estimation of the surface free energy of thin films of polyaniline doped with phosphoric acid, by measuring contact angles. Synthesis of polyaniline (PANI) with phosphoric acid (PA) was performed at room temperature of 20°C, and at 0°C. Thin films were obtained by means of a spin coater, applying the synthetized mixture on a glass substrate. By measuring the contact angle, first between ethylene glycol and a film and then between distilled water and a film, we thus calculated the polar, dispersion and total surface free energy. It was proved and demonstrated that the surface free energy depends on the temperature at which the solution (from which the thin films are obtained later) was synthesized.

This paper presents the process of obtaining thin films of polymer polyaniline that has been doped directly in the production process. Samples of thin films were obtained using a rotating disk method at different speeds. Polyaniline synthesis (PANI) was performed at 0°C and room temperature of 20°C. Doping was made with hydrochloric acid (PANI-HCl). We have shown what were the important factors that had influence on obtaining reproducible patterns of about the same characteristics. As indicators of these properties we measured electrical resistance, on the basis of which was calculated specific electrical conductivity of the obtained samples of thin films of polyaniline from different series of production.