Search results for "Nanoprobe"

Direct observation of elemental segregation in InGaN nanowires by X-ray nanoprobe

2011

Using synchrotron radiation nanoprobe, this work reports on the elemental distribution in single Inx Ga1–xN nanowires (NWs) grown by molecular beam epitaxy directly on Si(111) substrates. Single NWs dispersed on Al covered sapphire were characterized by nano-X-ray fluorescence, Raman scattering and photoluminescence spectroscopy. Both Ga and In maps reveal an inhomogeneous axial distribution inside sin- gle NWs. The analysis of NWs from the same sample but with different dimensions suggests a decrease of In segregation with the reduction of NW diameter, while Ga distribution seems to remain unaltered. Photoluminescence and Raman scattering measurements carried out on ensembles of NWs exhibi…

Silica-Based NIR Nano-Emitters for Applications in Vivo and Process for Production Thereof

2011

Production of paramagnetic and phosphorescent nanoprobes, obtainable starting from nanometric silica particles by methods of synthesis and enrichment with O2 following suitable thermal treatments in a controlled environment. The nanoprobes thus obtained display emission in the near infrared (NIR), are excitable in the visible and in the NIR, and are characterized by a lifetime of the order of one second. These nanoprobes have considerable scientific and commercial potential in the market of the confocal spectroscopy for bio-imaging and in the market of the medical pharmaceutical applications of drug labelling and drug delivery.

Physical properties and applications of InxGa1−xN nanowires

2014

We have successfully grown InxGa1−xN nanowires by plasma-assisted molecular beam epitaxy on silicon substrates. The alloy composition and crystal quality have been analyzed by Raman scattering, photoluminescence spectroscopy and x-ray fluorescence nanoprobe techniques. InxGa1−xN is an one-mode alloy, where the different optical modes have an intermediate frequency of that of pure InN and GaN. The sample composition can be derived from the Raman data. On the other hand, by using the optical gap provided by the emission spectra, we conclude that the samples have a lower Ga content than that provided by the Raman analysis. X-ray fluorescence maps and photoluminescence measured in single nanowi…

Characterization of single semiconductor nanowires by synchrotron radiation nanoprobe

2012

In this work, we report on the results of the characterization of single semiconductor nanowires by x-ray fluorescence nanoprobe. Wurtzite InGaN and Co-implanted ZnO single nanowires were studied. Ternary semiconductor nanowires show an axial inhomogeneous elemental distribution, with Ga accumulating at the bottom and In at the top of the wires. The ZnO NWs, on the other hand, show a homogeneous distribution of the Co implanted along the nanowires, without signatures of clustering or segregation effects induced by the implantation. No signatures of unintentional doping are observed neither in the InGaN nor the ZnO NWs. These overall results demonstrate the suitability of X-ray fluorescence …

Rapid and eco-friendly synthesis of graphene oxide-silica nanohybrids

2014

Étude des propriétés optiques et spectroscopiques de nanorods dopés au lanthanide pour des applications de nanosondes en champ proche

2022

Lanthanide-doped nanoparticles constitute a versatile family of photoluminescent local nanoprobes. In this work, we study the photoluminescence of Eu3+-doped NaYF4 nanorods characterized by highly polarized spectra. We develop a full theoretical model and paraxial approximation for nanorod dipole emission. We measure the photoluminescence of individual nanorods by fluorescence confocal microscopy and determine some of their intrinsic optical properties. We also determine the nature (electric or magnetic) and orientations of dipoles moments of the optical transitions used for nanoprobing in the visible range.In addition to the full theoretical model and the paraxial approximation, Fourier mi…

Gold nanoprobe-based detection of human telomerase reverse transcriptase (hTERT) Gene Expression

2015

Human Telomerase Reverse Transcriptase (hTERT) gene is expressed in all types of cancers, and it is considered as unique biomarker for early detection, monitoring and prognosis of different cancers. Routinely, the main techniques for detection of hTERT gene expression are based on enzymatic amplifications which need specified equipments, expert personnel and high cost and time. With regarding to the clinical importance of analysis of hTERT gene expression, we have developed a rapid, simple and low cost method which detects hTERT RNA target in 5 $\mu {\rm l}$ reaction scale using gold nanoprobes. The method is based on the inhibition of nanoparticle aggregation in the presence of ${\rm MgCl}…

Surface enhanced Raman scattering of silver sensitized cobalt nanoparticles in metal–dielectric nanocomposites

2008

We report the preparation of a new type of nanocomposite containing cobalt and silver nanoparticles organized in parallel layers with a well controlled separation. This arrangement allows the observation of an enhanced low-frequency Raman signal at the vibration frequency of cobalt nanoparticles excited through the surface plasmons of silver nanoparticles. Numerical simulations of the electric field confirm the emergence of hot spots when the separation between silver and cobalt nanoparticles is small enough. © IOP Publishing Ltd.