Periodic Arrays of Dopants in Silicon by Ultralow Energy Implantation of Phosphorus Ions through a Block Copolymer Thin Film.

In this work, block copolymer lithography and ultralow energy ion implantation are combined to obtain nanovolumes with high concentrations of phosphorus atoms periodically disposed over a macroscopic area in a p-type silicon substrate. The high dose of implanted dopants grants a local amorphization of the silicon substrate. In this condition, phosphorus is activated by solid phase epitaxial regrowth (SPER) of the implanted region with a relatively low temperature thermal treatment preventing diffusion of phosphorus atoms and preserving their spatial localization.

Hyperdoped Si nanocrystals embedded in silica for infrared plasmonics.

We present the experimental realization of plasmonic hyperdoped Si nanocrystals embedded in silica a combination of sequential low energy ion implantation and rapid thermal annealing. We show that phosphorus dopants are incorporated into the nanocrystal cores at concentrations up to six times higher than P solid solubility in bulk Si by combining 3D mapping with atom probe tomography and analytical transmission electron microscopy. We shed light on the origin of nanocrystal growth at high P doses, which we attribute to Si recoiling atoms generated in the matrix by P implantation, which likely increase Si diffusivity and feed the Si nanocrystals.

Infrared nanoplasmonic properties of hyperdoped embedded Si nanocrystals in the few electrons regime.

Using localized surface plasmon resonance (LSPR) as an optical probe we demonstrate the presence of free carriers in phosphorus doped silicon nanocrystals (SiNCs) embedded in a silica matrix. In small SiNCs, with radius ranging from 2.6 to 5.

Silica-induced electron loss of silver nanoparticles.

Despite the frequent use of silver nanoparticles (Ag NPs) embedded in materials for medical or optical applications, the effect of the matrix on the nanoparticle properties remains largely unknown. This study aims to shed light on the effect of an amorphous silica matrix on the structure and charge distribution of 55- and 147-atom silver nanoparticles by means of dispersion-corrected DFT calculations. Particular attention is paid to nanoparticle size and concentration effects and to the impact of the presence of native defects in the matrix.

Detection of the conformational changes of Discosoma red fluorescent proteins adhered on silver nanoparticles-based nanocomposites via surface-enhanced Raman scattering.

Description of the relationship between protein structure and function remains a primary focus in molecular biology, biochemistry, protein engineering and bioelectronics. Moreover, the investigation of the protein conformational changes after adhesion and dehydration is of importance to tackle problems related to the interaction of proteins with solid surfaces. In this paper the conformational changes of wild-type Discosoma recombinant red fluorescent proteins (DsRed) adhered on silver nanoparticles (AgNPs)-based nanocomposites are explored via surface-enhanced Raman scattering (SERS).

Physico-Chemical Characterization of the Interaction of Red Fluorescent Protein-DsRed With Thin Silica Layers.

The Discosoma recombinant red fluorescent (DsRed) protein is the latest member of the family of fluorescent proteins. It holds great promise for applications in biotechnology and cell biology. However, before being used for rational engineering, knowledge on the behavior of DsRed and the underlying mechanisms relating its structural stability and adsorption properties on solid surfaces is highly demanded.

Assessing bio-available silver released from silver nanoparticles embedded in silica layers using the green algae Chlamydomonas reinhardtii as bio-sensors.

Silver nanoparticles (AgNPs) because of their strong antibacterial activity are widely used in health-care sector and industrial applications. Their huge surface-volume ratio enhances the silver release compared to the bulk material, leading to an increased toxicity for microorganisms sensitive to this element. This work presents an assessment of the toxic effect on algal photosynthesis due to small (size <20nm) AgNPs embedded in silica layers.

Correction: Enhancing carrier generation in TiO2 by a synergistic effect between plasmon resonance in Ag nanoparticles and optical interference.

Correction for 'Enhancing carrier generation in TiO2 by a synergistic effect between plasmon resonance in Ag nanoparticles and optical interference' by Giuseppe Cacciato et al., Nanoscale, 2015, 7, 13468-13476.

Enhancing carrier generation in TiO2 by a synergistic effect between plasmon resonance in Ag nanoparticles and optical interference.

Silver nanoparticles have been embedded at a few nanometer distance from the free surface of titania/silica multilayers using low energy ion beam synthesis. Transmission electron microscopy shows the presence of 3 nm-sized crystalline particles. Reflectance spectroscopy on these composite substrates shows an increase of the light capture efficiency in the visible range.

Three dimensional design of silver nanoparticle assemblies embedded in dielectrics for Raman spectroscopy enhancement and dark-field imaging.

A strategy to design and fabricate hybrid metallic-dielectric substrates for optical spectroscopy and imaging is proposed. Different architectures consisting of three-dimensional patterns of metallic nanoparticles embedded in dielectric layers are conceived to simultaneously exploit the optical interference phenomenon in stratified media and localized surface plasmon resonances on metal nanoparticles. These structures are based on a simultaneous control of opto-electronic properties at three scales (3S) (~2/20/200 nm) and along three directions (3D).

Effect of ion implantation energy for the synthesis of Ge nanocrystals in SiN films with HfO2/SiO2 stack tunnel dielectrics for memory application.

Ge nanocrystals (Ge-NCs) embedded in SiN dielectrics with HfO2/SiO2 stack tunnel dielectrics were synthesized by utilizing low-energy (≤5 keV) ion implantation method followed by conventional thermal annealing at 800°C, the key variable being Ge+ ion implantation energy. Two different energies (3 and 5 keV) have been chosen for the evolution of Ge-NCs, which have been found to possess significant changes in structural and chemical properties of the Ge+-implanted dielectric films, and well reflected in the charge storage properties of the Al/SiN/Ge-NC + SiN/HfO2/SiO2/Si metal-insulator-semiconductor (MIS) memory structures. No Ge-NC was detected with a lower implantation energy of 3 keV at a dose of 1.

Phosphorus doping of ultra-small silicon nanocrystals.

P-doped Si nanocrystals (radius View Article and Find Full Text PDF

Stabilization of metastable phases in spatially restricted fields: the case of the Fe2O3 polymorphs.

In this work we show how the confinement of particles in a silica matrix with pores, acting as nano-vessels, plays an important role in the formation of pure E-Fe2O3 nanoparticles and their thermal stability. In particular, a HRTEM study of a series of Fe2O3-SiO2 xerogels annealed at different temperatures reveals that, at low temperatures, gamma-Fe2O3 nanoparticles are formed and only transform to F-Fe2O3 after subsequent annealing at higher temperatures. These data are complemented by measurements of the SiO2 matrix porosity as well as with calorimetric and structural analysis of the nanoparticles after matrix removal.