Publications

2009

• Kelvin probe force microscopy of charge transfer mechanisms from doped silicon nanocrystals
  
  • Borowik Lukasz
  • Kusiaku Koku
  • Deresmes D.
  • Theron Didier
  • Diesinger Heinrich
  • Melin Thierry
  • Nguyen-Tran Thuat
  • Roca I Cabarrocas Pere
  , 2009. The introduction of impurities in semiconductor nanocrystals is of fundamental interest to control their optical, electrical and magnetic properties[1]. Doping is essential to basically enhance electrical conductivity, and to build functional devices. This issue becomes of prime interest at the nanoscale for e.g. self-assembled devices based on organic, molecular or inorganic nanostructures, for which the control of doping can be either technologically difficult during the synthesis, and strongly depend on the environment, as in the case of carbon nanotubes[2] or physically limited, as in the case of silicon nanowires for which internal doping becomes unefficient due to dielectric screening[3].In this presentation, we investigate using ultra-high vacuum non-contact atomic force microscopy and Kelvin probe force microscopy (KFM) the possibility of using doped nanocrystals as electron sources to perform external remote doping of nanostructures and nanodevices. The focus is here to study the mechanisms of charge transfer from nanocrystals at the scale of the individual nanocrystals. To do so, we study the charge transfer from hydrogen-passivated phosphorus-doped[4] silicon nanocrystals towards silicon substrates by means of amplitude-modulation KFM. From the measurement of the electrostatic potential of ionized nanocrystals, we demonstrate that the nanocrystal doping (i) provides an internal passivation of the nanocrystal surface states and (ii) induces a charge transfer following an energy compensation mechanism similar to remote doping, but strongly enhanced by quantum confinement. Results provide a direct measurement of the nanocrystal band-gap opening induced by quantum confinement in the 2-50nm range[5], in agreement with parametrized tight-binding calculations. They also put forward the possibility of using doped nanocrystals to achieve controlled external remote doping of nanostructures and nanodevices, with expected two-dimensional charge densities in the range of 10^11-10^14 cm-2, or linear charge densities in the range of 10^5-10^7 cm-1.References: [1] For a recent review, see: D.J. Norris, A. L. Efros, S. C. Erwin, Science 319,776-1779 (2008) ; S. C. Erwin, L. Zu, M. I. Haftel, A. L. Efros, T. A. Kennedy, and D. J. Norris, Nature 36,91 (2005).; D. Yu, C.J. Wang, and P. Guyot-Sionnest, Science 300, 1277 (2003).[2] V. Derycke, R. Martel, J. Appenzeller, and Ph. Avouris, Appl. Phys. Lett. 80, 2773 (2002).[3] M. T. Bjork, H. Schmid, J. Knoch, H. Riel, W. Riess, Nature Nanotechnology 4, 103-107 (2009); M. Diarra, Y. M. Niquet, C. Delerue, and G. Allan, Phys. Rev. B 75, 045301 (2007).[4] A. R. Stegner, R. N. Pereira, K. Klein, R. Lechner, R. Dietmueller, M. S. Brandt, M. Stutzmann and H. Wiggers, Phys. Rev. Lett. 100, 026803 (2008).[5] L. Borowik, K. Kusiaku, D. Théron, D. Deresmes, H. Diesinger, T. Mélin, T. Nguyen-Tran, P. Roca i Cabarrocas (submitted to Phys. Rev. Lett.)
• Electrostatic grafting of diamond nanoparticles: a versatile route to nanocrystalline diamond thin films
  
  • Girard Hugues
  • Perruchas Sandrine
  • Gesset Celine
  • Chaigneau Marc
  • Vieille Laetitia
  • Arnault Jean-Charles
  • Bergonzo Philippe
  • Boilot Jean-Pierre
  • Gacoin Thierry
  ACS Applied Materials & Interfaces, Washington, D.C. : American Chemical Society, 2009, 1 (12), pp.2738 - 2746. Nanodiamond (ND) seeding is a well-established route toward the CVD (chemical vapor deposition) synthesis of diamond ultrathin films. This method is based on the deposition onto a substrate of diamond nanoparticles which act as pre-existing sp$^3$ seeds. Here, we report on a straightforward method to disperse diamond nanoparticles on a substrate by taking advantage of the electrostatic interactions between the nanodiamonds and the substrate surface coated with a cationic polymer. This layer-by-layer deposition technique leads to reproducible and homogeneous large-scale nanoparticle deposits independent of the substrate’s nature and shape. No specific functionalization of the nanoparticles is required, and low concentrated solutions can be used. The density of ND on the substrate can be controlled, as shown by in situ ATR-FTIR (attenuated total reflection Fourier transform infrared) analysis and QCM (quartz crystal microbalance) measurements. Highly dense and compact ND deposits can be obtained, allowing CVD growth of nanocrystalline diamond ultrathin films (70 nm) on various substrates. The synthesis of 3D structured and patterned diamond thin films has also been demonstrated with this method. (10.1021/am900458g)
  DOI : 10.1021/am900458g
• 2,2'-Bipyrimidine as Efficient Sensitizer of the Solid State Luminescence of Lanthanide and Uranyl Ions from Visible to Near Infrared
  
  • Zucchi Gaël
  • Maury Olivier
  • Thuéry Pierre
  • Gumy F.
  • Bunzli Jean-Claude
  • Ephritikhine M.
  Chemistry - A European Journal, Wiley-VCH Verlag, 2009, 15, pp.9686. Treatment of LnACHTUNGTRENUNG(NO3)3*nH2O with 1 or 2 equiv 2,2'-bipyrimidine (BPM) in dry THF readily afforded the monometallic complexes [LnACHTUNGTRENUNG(NO3)3- ACHTUNGTRENUNG(bpm)2] (Ln=Eu, Gd, Dy, Tm) or [Ln- ACHTUNGTRENUNG(NO3)3ACHTUNGTRENUNG(bpm)2]*THF (Ln=Eu, Tb, Er, Yb) after recrystallization from MeOH or THF, respectively. Reactions with nitrate salts of the larger lanthanide ions (Ln=Ce, Nd, Sm) yielded one of two distinct monometallic complexes, depending on the recrystallization solvent: [LnACHTUNGTRENUNG(NO3)3ACHTUNGTRENUNG(bpm)2]*THF (Ln=Nd, Sm) from THF, or [LnACHTUNGTRENUNG(NO3)3ACHTUNGTRENUNG(bpm)- ACHTUNGTRENUNG(MeOH)2]*MeOH (Ln=Ce, Nd, Sm) from MeOH. Treatment of UO2- ACHTUNGTRENUNG(NO3)2*6H2O with 1 equiv BPM in THF afforded the monoadduct [UO2- ACHTUNGTRENUNG(NO3)2ACHTUNGTRENUNG(bpm)] after recrystallization from MeOH. The complexes were characterized by their crystal structure. Solid-state luminescence measurements on these monometallic complexes showed that BPM is an efficient sensitizer of the luminescence of both the lanthanide and the uranyl ions emitting visible light, as well as of the YbIII ion emitting in the near-IR. For Tb, Dy, Eu, and Yb complexes, energy transfer was quite efficient, resulting in quantum yields of 80.0, 5.1, 70.0, and 0.8%, respectively. All these complexes in the solid state were stable in air. (10.1002/chem.200901517)
  DOI : 10.1002/chem.200901517
• Charge transfer from doped silicon nanocrystals
  
  • Borowik Lukasz
  • Kusiaku Koku
  • Theron Didier
  • Diesinger Heinrich
  • Deresmes D.
  • Melin Thierry
  • Nguyen-Tran Thuat
  • Roca I Cabarrocas Pere
  , 2009.
• Charge transfer from doped silicon nanocrystals
  
  • Borowik Lukasz
  • Kusiaku Koku
  • Theron Didier
  • Diesinger Heinrich
  • Deresmes D.
  • Melin Thierry
  • Nguyen-Tran Thuat
  • Roca I Cabarrocas Pere
  , 2009.
• Molecular beam epitaxy of SrTiO3 on Si (001): Early stages of the growth and strain relaxation
  
  • Niu Gang
  • Saint-Girons Guillaume
  • Vilquin Bertrand
  • Delhaye Gabriel
  • Maurice Jean-Luc
  • Botella Claude
  • Robach Yves
  • Hollinger Guy
  Applied Physics Letters, American Institute of Physics, 2009, 95 (6), pp.2902. The molecular beam epitaxy of SrTiO3 (STO) layers on Si (001) is studied, focusing on the early stages of the growth and on the strain relaxation process. Evidence is given that even for optimized growth conditions, STO grows initially amorphous on silicon and recrystallizes, leading to the formation of an atomically abrupt heterointerface with silicon. Just after recrystallization, STO is partially strained. Further increase in its thickness leads to the onset of a progressive plastic relaxation mechanism. STO recovers its bulk lattice parameter for thicknesses of the order of 30 ML. (10.1063/1.3193548)
  DOI : 10.1063/1.3193548
• Conductance of disordered semiconducting nanowires and carbon nanotubes: a chain of quantum dots
  
  • Dayen J.-F.
  • Wade T.L.
  • Rizza G.
  • Golubev D.S.
  • Cojocaru C.-S.
  • Pribat D.
  • Jehl X.
  • Sanquer M.
  • Wegrowe J.-E.
  European Physical Journal: Applied Physics, EDP Sciences, 2009, 48 (1), pp.1-14. A comparative study of the low temperature conductivity of an ensemble of multiwall carbon nanotubes and semiconductor nanowires is presented. The quasi one-dimensional samples are made in nanoporous templates by electrodeposition and CVD growth. Three different structures are studied in parallel: multiwall carbon nanotubes, tellurium nanowires, and silicon nanowires. It is shown that the Coulomb blockade regime dominates the electronic transport below 50 K, together with weak and strong localization effects. In the Coulomb blockade regime, a scaling law of the conductance measured as a function of the temperature and the voltage is systematically observed. This allows a single scaling parameter to be defined. This parameter accounts for the specific realization of the “disorder”, and plays the role of a fingerprint for each sample. Correlations between and the conductance measured as a function of temperature and voltage, as a function of the perpendicular magnetic field, and as a function of the temperature and voltage in the localized regime below 1 K have been performed. Three universal laws are reported. They relate the coefficient (1) to the normalized Coulomb blockade conductance , (2) to the phase coherence length , and (3) to the activation energy . These observations suggest a description of the wires and tubes in terms of a chain of quantum dots; the wires and tubes break into a series of islands. The quantum dots are defined by conducting islands with a typical length on the order of the phase coherence length separated by poorly conducting regions (low density of carriers or potential barriers due to defects). A corresponding model is developed in order to put the three universal laws in a common frame. (10.1051/epjap/2009132)
  DOI : 10.1051/epjap/2009132
• Isolation of Dysprosium and Yttrium Complexes of a Three-Electron Reduction Product in the Activation of Dinitrogen, the N23- Radical
  
  • Zucchi Gaël
  • Evans W.J.
  • Fang Ming
  • Furche Filipp
  • Ziller J.W.
  • Hoekstra R.M.
  • Zink J.I.
  Journal of the American Chemical Society, American Chemical Society, 2009, 131, pp.11191. DyI2 reacts with 2 equiv of KOAr (OAr ) OC6H3(CMe3)2-2,6) under nitrogen to form not only the (N2)2- complex, [(ArO)2(THF)2Dy]2(μ-η2:η2-N2), 1, but also complexes of similar formula with an added potassium ion, [(ArO)2(THF)Dy]2(μ-η2:η2-N2)[K(THF)6], 2, and [(ArO)2(THF)Dy]2(μ3-η2:η2:η2-N2)K(THF), 3. The 1.396(7) and 1.402(7) Å N-N bond distances in 2 and 3, respectively, are consistent with an (N2)3- ligand, but the high magnetic moment of 4f9 Dy3+ precluded definitive identification. The Y[N(SiMe3)2]3/K reduction system was used to synthesize yttrium analogues of 2 and 3, {[(Me3Si)2N]2(THF)Y}2(μ-η2:η2- N2)[K(THF)6] and {[(Me3Si)2N]2(THF)Y}2(μ3-η2:η2:η2-N2)K, that had similar N-N distances and allowed full characterization. EPR, Raman, and DFT studies are all consistent with the presence of (N2)3- in these complexes. 15N analogues were also prepared to confirm the spectroscopic assignments. The DFT studies suggest that the unpaired electron is localized primarily in a dinitrogen π orbital isolated spatially, energetically, and by symmetry from the metal orbitals. (10.1021/ja9036753)
  DOI : 10.1021/ja9036753
• Tip enhanced Raman spectroscopy on azobenzene thiol self-assembledmonolayers on Au(111)
  
  • Picardi Gennaro
  • Chaigneau Marc
  • Ossikovski Razvigor
  • Licitra Christophe
  • Delapierre G.
  Journal of Raman Spectroscopy, Wiley, 2009, 40, pp.1407-1412. Tip enhanced Raman spectroscopy (TERS) and imaging experiments in tunnelling (gap) mode were performed on a 2 nm thick azobenzene thiol monolayer grafted on Au(111). A strong dependence on the tunnelling parameters, regulating the gold tip-gold surface gap distance,was observed for the intensity of the enhanced Raman signal. The influence of the incident light polarization is also discussed. (10.1002/jrs.2362)
  DOI : 10.1002/jrs.2362
• Heterogeneous vortex dynamics in high temperature superconductors
  
  • Yang Feng
  , 2009. In high temperature superconductors with strong pinning, the change in shear properties of the vortex system is a plausible mechanism for the vanishing of the linear electrical resistance at the transition from vortex liquid to vortex solid. The divergence of the shear viscosity of the vortex liquid upon cooling is, in this respect, an ominent sign of a phase transition to an ensemble of localized vortices. By introducing a channel-confined structure on macroscopic defect-free $Bi_{2}Sr_{2}CaCu_{2}O_{8}$ single crystals using heavy ion irradiation, we have succeeded in probing the shear viscosity of the vortex liquid directly. Magneto-optical imaging shows that 20 $\mu$m wide pin-free channels separated by 20 $\mu$m wide strongly pinning walls were made successfully. The vortex liquid shear viscosity was then obtained from transport measurements. Contrary to previous studies, the present work focuses on very low magnetic fields, of the order of hundreds of Gauss. The vortex liquid shear viscosity, even in low fields, can be equally well fitted by the Nelson-Halperin theory for the dislocation density in a two-dimensional vortex fluid as by the power laws derived in the framework of vortex glass models. This result shows that the vortex ensemble in the confined medium behaves as a system of rectilinear lines, with edge dislocations threading the system from end to end. The progressive jamming of the vortex ensemble upon cooling mimics a vortex liquid to vortex glass transition. This finds an analogy with recently reported shear-induced solid-to-fluid transitions in soft glassy materials.
• Analysis of depolarizing Mueller matrices through a symmetric decomposition
  
  • Ossikovski Razvigor
  Journal of the Optical Society of America. A Optics, Image Science, and Vision, Optical Society of America, 2009, pp.1109.
• Miscibility Between Differently-Shaped Mesogens: Structural and Morphological Study of a Phthalocyanine-Perylene Binary System
  
  • Zucchi Gaël
  • Viville Pascal
  • Donnio Bertrand
  • Vlad Alexandru
  • Melinte Sorin
  • Mondeshki Mihail
  • Graf Robert
  • Spiess H.W.
  • Geerts Yves Henry
  • Lazzaroni Roberto
  Journal of Physical Chemistry B, American Chemical Society, 2009, 113 (16), pp.5448. The thermotropic, structural, and morphological properties of blends of a disk-like liquid crystalline phthalocyanine derivative and a lath-shaped perylenetetracarboxidiimide mesogen derivative have been studied by combining differential scanning calorimetry, thermal polarized optical microscopy, X-ray diffraction, solidstate nuclear magnetic resonance, and atomic force microscopy. The two compounds are fully miscible for blends containing at least 60 mol % of the disk-like molecule. In such composition range, the homogeneous blends form a columnar hexagonal (Colh) mesophase for which the thermal stability is enhanced compared to that of the corresponding mesophase of the pure phthalocyanine. The miscible blends self-align homeotropically between two glass slides. For blends containing between 55 and 40 mol % of the diskshaped molecule, the two components are fully miscible at high temperature but the perylene derivative forms a separate crystalline phase when the temperature is decreased. Phase separation is systematically observed in blends containing less than 40 mol % of the discotic molecule. In this case, the resulting Colh mesophase is less stabilized compared to the blends containing a larger amount of the phthalocyanine derivative. These phase-separated blends do not show any homeotropic alignment. AFM investigations confirm the formation of a single columnar morphology in the phthalocyanine-rich blends, consistent with the full miscibility between the two compounds. Solid-state NMR measurements on the mixed phase show the influence of the presence of the perylene molecules on the molecular dynamics of the molecules; remarkably, the presence of the host molecules improves the local order parameter in the phthalocyanine columnar phase. (10.1021/jp809591h)
  DOI : 10.1021/jp809591h
• Electrostatic properties of doped silicon nanocrystals probed by Kelvin force microscopy
  
  • Borowik Lukasz
  • Kusiaku Koku
  • Theron Didier
  • Diesinger Heinrich
  • Deresmes D.
  • Melin Thierry
  • Nguyen-Tran Thuat
  • Roca I Cabarrocas Pere
  , 2009.
• Low-temperature growth of nano-structured silicon thin films on ITO initiated by metal catalysts
  
  • Alet Pierre-Jean
  • Palacin Serge
  • Roca I Cabarrocas Pere
  Thin Solid Films, Elsevier, 2009, 517, pp.6405-6408. Nano-structured silicon thin films have been grown on tin-doped indium oxide (ITO) by Plasma-Enhanced Chemical Vapor Deposition (PECVD) at temperatures lower than 200ºC. Nanometer-scaled aggregates of metal (copper or gold) obtained from evaporated layers were necessary to initiate the nano-structuring growth. Different deposition conditions have been investigated. The highest aspect ratio was obtained with copper and high-pressure plasmas with SiH4 diluted in H2. The metals help dissociating silane so the deposition starts faster on the aggregates than around them, which leads to the nano-structuration. It is likely that the metal remains confined at the interface between ITO and silicon and do not diuse in the silicon layer. (10.1016/j.tsf.2009.02.106)
  DOI : 10.1016/j.tsf.2009.02.106
• Selective electroless copper deposition on self-assembled dithiol monolayers
  
  • Aldakov Dmitry
  • Bonnassieux Yvan
  • Geffroy Bernard
  • Palacin Serge
  ACS Applied Materials & Interfaces, Washington, D.C. : American Chemical Society, 2009, 1, pp.584-589. The paper reports the use of self-assembled monolayers (SAMs) of dithiols to induce electroless copper deposition on a gold substrate. The metallization catalyst, palladium nanoparticles, is bound on the dithiol SAM. The assembly process is followed by IR and X-ray photoelectron spectroscopies to confirm the formation of a monolayer with bound catalyst. Electroless metallization is then carried out with a steady deposition rate of 130 nm/min. Additionally, microcontact printing of the catalyst on the SAM by poly(dimethylsiloxane) stamps is used to localize copper deposits. Resulting metallization is selective and allows for a high resolution. (10.1021/am8001346)
  DOI : 10.1021/am8001346
• Photonic band measurement by angle-resolved spectroscopy and polarimetry
  
  • Kral Zdenek
  • Garcia-Caurel Enric
  • Ferre-Borrull Josep
  • Marsal Lluis F.
  • Pallarès J.
  , 2009, CDE 2009, pp.394.
• Tip-enhanced Raman scattering: Influence of the tip-surface geometry on optical resonance and enhancement
  
  • Pettinger Bruno
  • Domke Katrin F.
  • Zhang Dai
  • Picardi Gennaro
  • Schuster Rolf
  Surface Science : A Journal Devoted to the Physics and Chemistry of Interfaces, Elsevier, 2009, 603, pp.1335-1341. The tip-sample distance (z) dependence of tip-enhanced Raman scattering (TERS) has been investigated. The intensities of both, the Raman lines and the broad TERS background, exhibit strong decays with increasing z, which are nearly complete within 10 nm withdrawal of the STM tip in z direction. Interestingly, the maximum of the broad Lorentzian-shaped TER background is substantially blue shifted in energy with z. This effect is ascribed to a corresponding blue shift of the energies of localized plasmon modes upon tip retraction. Both experimental results fit very well data of a simple theoretical near-field model.
• Characterization of grating structures by Mueller polarimetry in presence of strong depolarization due to finite spot size and spectral resolution
  
  • Foldyna Martin
  • Garcia-Caurel Enric
  • de Martino Antonello
  • Ossikovski Razvigor
  • Licitra C.
  Optics Communications, Elsevier, 2009, 282, pp.735.
• Toward full carbon interconnects: High conductivity of individual carbon nanotube to carbon nanotube regrowth junctions
  
  • Tuukkanen Sampo
  • Streiff Stephane
  • Chenevier Pascale
  • Pinault M.
  • Jeong Hee J.
  • Enouz-Vedrenne Shaima
  • Cojocaru Costel Sorin
  • Pribat Didier
  • Bourgoin Jean P.
  Applied Physics Letters, American Institute of Physics, 2009, 95, pp.113108. A versatile chemical vapor deposition (CVD) based method for the fabrication and electrical measurement of individual carbon nanotube junctions was developed. ferritin or Fe particles were grafted on multiwalled carbon nanotubes (MWNTs) and used as catalysts for the subsequent growth of secondary MWNT by CVD. Junctions were then individually connected. The conductivities of the MWNTs and of the junction were measured. Statistical data show that the conductance of the MWNT-MWNT junction is similar to that of MWNT. This result paves the way for the use of carbon nanotubes as electrical interconnects in electronic applications. (10.1063/1.3216839)
  DOI : 10.1063/1.3216839
• Sources of possible artefacts in the contrast evaluation for the backscattering polarimetric images of different targets in turbid medium
  
  • Novikova Tatiana
  • Bénière Arnaud
  • Goudail François
  • de Martino Antonello
  Optics Express, Optical Society of America - OSA Publishing, 2009, 17 (26), pp.23851-23860. It is known that polarization-sensitive backscattering images of different objects in turbid media may show better contrasts than usual intensity images. Polarimetric image contrast depends on both target and background polarization properties and typically involves averaging over groups of pixels, corresponding to given areas of the image. By means of numerical modelling we show that the experimental arrangement, namely, the shape of turbid medium container, the optical properties of the container walls, the relative positioning of the absorbing, scattering and reflecting targets with respect to each other and to the container walls, as well as the choice of the image areas for the contrast calculations, can strongly affect the final results for both linearly and circularly polarized light.
• Calculation of angular-dependent reflectance and polarimetry spectra of nanoporous anodic alumina-based photonic crystal slabs
  
  • Kral Zdenek
  • Vojkuvka L.
  • Garcia-Caurel Enric
  • Ferre-Borrull Josep
  • Marsal Lluis F.
  • Pallares Josep
  Photonics and Nanostructures - Fundamentals and Applications, Elsevier, 2009, 7, pp.12.
• Pulsed laser deposited tetrahedral amorphous carbon with high sp3 fractions and low optical bandgaps
  
  • Miyajima Y.
  • Henley S. J.
  • Adamopoulos Georges
  • Stolojan V.
  • Garcia-Caurel Enric
  • Drevillon Bernard
  • Shannon J.M.
  • Silva S.R.P.
  Journal of Applied Physics, American Institute of Physics, 2009, 105, pp.073521.
• Capillary jet injection of SiH4 in the high density plasma chemical vapor deposition of SiO2
  
  • Botha Roelene
  • Novikova Tatiana
  • Bulkin Pavel
  Journal of Vacuum Science & Technology A, American Vacuum Society, 2009, 27 (4), pp.849.
• Conductance of disordered semiconducting nanowires and carbon nanotubes: a chain of quantum dots
  
  • Dayen Jf
  • Wade Tl
  • Rizza G.
  • Golubev Ds
  • Cojocaru C.S.
  • Pribat D.
  • Jehl X.
  • Sanquer M.
  • Wegrowe J.E.
  European Physical Journal: Applied Physics, EDP Sciences, 2009, 48 (1), pp.10604. A comparative study of the low temperature conductivity of an ensemble of multiwall carbon nanotubes and semiconductor nanowires is presented. The quasi one-dimensional samples are made in nanoporous templates by electrodeposition and CVD growth. Three different structures are studied in parallel: multiwall carbon nanotubes, tellurium nanowires, and silicon nanowires. It is shown that the Coulomb blockade regime dominates the electronic transport below 50 K, together with weak and strong localization effects. In the Coulomb blockade regime, a scaling law of the conductance measured as a func- tion of the temperature and the voltage is systematically observed. This allows a single scaling parameter α to be defined. This parameter accounts for the specific realization of the "disorder", and plays the role of a fingerprint for each sample. Correlations between α and the conductance measured as a function of temperature and voltage, as a function of the perpendicular magnetic field, and as a function of the temperature and voltage in the localized regime below 1 K have been performed. Three universal laws are reported. They relate the coefficient α (1) to the normalized Coulomb blockade conductance GT (α), (2) to the phase coherence length lφ (α), and (3) to the activation energy Ea(α). These observations suggest a description of the wires and tubes in terms of a chain of quantum dots; the wires and tubes break into a series of islands. The quantum dots are defined by conducting islands with a typical length on the order of the phase coherence length separated by poorly conducting regions (low density of carriers or potential barriers due to defects). A corresponding model is developed in order to put the three universal laws in a common frame. (10.1051/epjap/2009132)
  DOI : 10.1051/epjap/2009132
• Retrieval of non-depolarizing components of depolarizing Mueller matrices
  
  • Foldyna Martin
  • Garcia-Caurel Enric
  • Ossikovski Razvigor
  • de Martino Antonello
  • Gil José Jorge
  Optics Express, Optical Society of America - OSA Publishing, 2009, 17, pp.12794.