spectroscopy Articles
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Ultrafast laser spectroscopy of semiconductor nanocrystals
Ultrafast laser spectroscopy is an efficient tool for investigation of ultrafast processes in nanostructures. We have been involved in the picosecond and femtosecond laser spectroscopy of semiconductor nanocrystals since the mid–1990s. This paper aims to review some of our results and to illustrate the potential of ultrafast laser spectroscopy in the research of semiconductor ...
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Determination of the mechanism behind the organic magnetoresistance (OMAR) effect by using impedance spectroscopy
We investigated the organic magnetoresistance (OMAR) mechanism in poly(3–hexylthiophene–2,5–diyl) (P3HT)–based diodes, by using impedance spectroscopy. We have prepared layered structures consisting of indium tin oxide, poly(3,4–ethylenedioxythiophene):poly(styrenesulphonate) (PEDOT:PSS), P3HT and aluminium and measured the bias voltage dependence of the OMAR and of the impedance spectra. The ...
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SrTi
1xNixO3nanoparticles: synthesis and characterisationWe present the synthesis of SrTi1xNixO3 (STNO) (x = 0.00, 0.10, 0.20, 0.30, 0.40, 0.50) nanoparticles and investigate their structure, absorption spectra, temperature-dependent Raman spectroscopy, impedance spectroscopy and magnetic property. Nanoparticles of STNO were prepared by sol-gel method. The particle size is smaller than 30 nm and depends on the Ni-substituted content. The experimental ...
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Fundamental studies in nanosciences at the Institute of Electronics, Microelectronics, and Nanotechnology (IEMN)
This paper gives an overview over the fundamental research in nanosciences at the Institute of Electronics, Microelectronics and Nanotechnology (IEMN). We present some highlights from the numerical simulation of the electronic structure of nanowires and nanotubes, the charge spectroscopy of Si nanoparticles and C nanotubes, the scanning tunnelling spectroscopy of semiconductor quantum dots, to ...
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Application of surface complexation models to anion adsorption by natural materials
Various chemical models of ion adsorption will be presented and discussed. Chemical models, such as surface complexation models, provide a molecular description of anion adsorption reactions using an equilibrium approach. Two such models, the constant capacitance model and the triple layer model will be described. Characteristics common to all the surface complexation models are equilibrium ...
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Spectroscopic analysis of boron porphyrin complexes
Spectroscopic analyses of diboron porphyrin complexes have been performed using femtosecond transient absorption spectroscopy, fluorescence spectroscopy measurements, IR and Raman spectroscopy as well as DFT and TDDFT calculations. Transient absorption spectroscopy was used to study the dynamics of the transient species by exciting the molecule with a ~100 fs pulse of light at the wavelength ...
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Investigation of Ge/Si quantum dot structures using the methods of admittance spectroscopy
In this paper the properties of multilayer p–i–n–structures based on Si with Ge quantum dots fabricated by molecular beam epitaxy were investigated using the method of admittance spectroscopy at temperatures from 10 K to 300 K. The results of experimental research for two types of structures are presented. The activation energies of the emission process from localised states are ...
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Nanometric metal wire as a guide for THz investigation of living cells
The development of microsystems as tools for nanotechnology is strongly observed in the case of Biological MicroElectroMechanical Systems (BioMEMS). A part of them aim at the characterisation of biomolecules in solutions or in biological entities such as living cells. THz spectroscopy could provide interesting new complementary information at the systemic biology due to its faculty to probe the ...
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Nanoparticles and nanowires: synchrotron spectroscopy studies
This paper reviews the research in nanomaterials conducted in our laboratory in the last decade using conventional and synchrotron radiation techniques. While preparative and conventional characterisation techniques are described, emphasis is placed on the analysis of nanomaterials using synchrotron radiation. Materials of primary interests are metal nanoparticles and semiconductor nanowires and ...
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Bulk viscosity and compressibility measurement using acoustic spectroscopy
Bulk viscosity is a somewhat obscure parameter that appears in the hydrodynamic equations for Newtonian liquids when compressibility is important and, together with the dynamic viscosity, controls sound attenuation. Whereas dynamic viscosity reflects only “translational” molecular motion, in contrast the bulk viscosity reflects the relaxation of both “rotational” and “vibrational” degrees of ...
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Spectroscopic investigation of II–VI core-shell nanoparticles: CdSe/CdS
CdSe and CdSe/CdS core/shell nanoparticles were prepared by a one-pot synthesis process. The CdSe/CdS core/shell nanoparticles showed red-shift absorption and emission spectra compared to the CdSe core. An optimal reaction time for CdS to form on the CdSe nanoparticles was evaluated and the highest photoluminescence yield of approximately equal to 20% was observed for the core/shell ...
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Microstructural study of thermally treated reactor pressure vessel steels using spectroscopic methods
Positron annihilation spectroscopy (lifetime and Doppler broadening techniques), transmission Mössbauer spectroscopy, integral low-energy electron Mössbauer spectroscopy and transmission electron microscopy were applied to examine thermally treated reactor pressure vessel steels (RPV). The results of these methods obtained for different types of steels are discussed and correlated with hardness ...
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Effects of deformation and physical aging on nano-scale free volumes in polycarbonate studied by positron annihilation lifetime spectroscopy
Positron annihilation lifetime spectroscopy (PALS) has been employed to measure the variation of free volume hole parameters in poly(carbonate) (PC) after plastic deformation below the glass transition temperature (Tg). Changes in nano-scale free volume holes (Vh) and in their fraction (%fv) due to plane-strain and uniaxial compression and aging time were investigated at temperatures below Tg. ...
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Adsorption of lead using a novel xanthated carboxymethyl chitosan
Adsorption of Pb(II) was studied using a novel xanthated carboxymethyl chitosan (XCC). The XCC was synthesized using the xanthation reaction of N-carboxymethyl chitosan (NCMC). The chemical structure of XCC was characterized by UV–visible spectra. The effects of initial pH value of the solutions, contact time and adsorption isotherms on adsorption of Pb(II) were investigated. Moreover, ...
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Rotating angled plate diffusing wave spectroscopy
Solid–like non–ergodic samples can be difficult to study using standard single speckle diffusing wave spectroscopy as the measurement may lack requisite ensemble averaging. We demonstrate here that this required ensemble averaging can be induced by translating the speckle over the collection optics so that multiple speckles are observed over the duration of the experiment. Translation is achieved ...
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PyTrA: ultra–fast transient absorption data analysis software
Ultra–fast transient absorption spectra are inherently complex data sets to process. PyTrA is a new software system that has been written to bring together many of the most well–known techniques of analysis into one easy–to–use package. Figure of publishable quality can be generated, and advanced 3D graphs can be used to view the transient data in new ways. PyTrA is the first ultrafast transient ...
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Nanoholes in metals with applications to sensors and spectroscopy
In this paper, we review our experimental and theoretical investigations of nano-holes in metal films. Our first contribution to this field was to demonstrate experimentally that the shape of the holes in arrays could be used to influence the optical properties; in particular, we showed how to control the polarisation with elliptical nano-holes. A theory explaining this shape-effect was presented ...
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The Technology Behind GasFinder
This is a group of tutorials and papers based on the scientific principles of open path gas measurement, a broad collection intended for those who are unfamiliar with infra-red laser-based ...
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OEM solutions help to popularize TDLS
The latest case study published in AWE Magazine (March 2016 Edition) focuses on trends in gas detection solutions based on Tunable Diode Laser Spectroscopy (TDLS). OEM solutions based on TDLS are offered at low costs for high volume applications, and are customized to meet specific application demands. Read and download the complete case study ...
By Axetris AG
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Positron annihilation rates in materials
The study of positron annihilation rate is one subject of a relatively new method of material structure analysis ? positron annihilation spectroscopy. Polyethylene Terephthalate (PET) films have been studied by positron annihilation rate measurement. The correlation between annihilation rates and the PET film thickness was established. Similar studies were carried out for aluminium foils and ...
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