Search results for "ELECTRICAL RESISTIVITY"
showing 10 items of 357 documents
Scattering Processes in Nanocarbon-Based Nanointerconnects
2017
Cluster approach based on the multiple scattering theory (MST) formalism, realistic analytical and coherent potentials as well as effective medium approximation (EMA–CPA) can be effectively used for nanosized systems modelling. Major attention is paid now to applications of carbon nanotubes (CNTs) and graphene nanoribbons (GNRs) with various morphology which possess unique physical properties in nanoelectronics, e.g. contacts of CNTs or GNRs with other conducting elements of a nanocircuit, which can be promising candidates for interconnects in high-speed electronics. The main problems connected with the resistance of C–Me junctions with metal particles appear due to the influence of chirali…
Conductive nanostructures of MMX chains
2010
Crystals of [Pt-2(n-pentylCS(2))(4)I] show a transition from semiconductor to metallic with the increase of the temperature (conductivity is 0.3-1.4 S.cm(-1) at room temperature) and a second metallic metallic transition at 330 K, inferred by electrical conductivity measurements. X-ray diffraction studies carried out at different temperatures (100, 298, and 350 K) confirm the presence of three different phases. The valence-ordering of these phases is analyzed using structural, magnetic, and electrical data. Density functional theory calculations allow a further analysis of the band structure derived for each phase. Nanostructures adsorbed on an insulating surface show electrical conductivit…
Electropolymerization of non-substituted Mg(II) porphine: Effects of proton acceptor addition
2015
Abstract Electropolymerization of unsubstituted magnesium porphine in acetonitrile solutions possessing various proton-accepting properties has been studied. The overall rate of the polymer-product accumulation on the electrode surface has been established to be limited by the deprotonation step of intermediate species. This conclusion is based on the observed influence of proton-accepting additives, water or 2,6-dimethylpyridine (lutidine), on the Mg-porphine electrooxidation process. Lutidine addition into the polymerization bath enables one to enhance strongly the rate of the film growth and the efficiency of this process increases more than by a factor of two, redox, electric conductivi…
Short range charge/orbital ordering in La1−xSrxMn1−zBzO3 (B = Cu,Zn) manganites
2005
We have measured the reflectivity spectra of La1−x SrxMn1−zBzO3 (B = Cu, Zn; 0.17 x 0.30; 0 z 0.10) manganites over wide frequency (100–4000 cm −1 )a nd temperature (80–300 K) ranges. Besides the previously observed infrared active modes or mode pairs at about 160 cm −1 (external mode), 350 cm −1 (bond bending mode) and 590 cm −1 (bond stretching mode), we have clearly observed two additional phonon modes at about 645 and 720 cm −1 below the temperature T1 (T1 < TC), which coincides with the phase transition temperature when the system transforms from ferromagnetic metallic into a ferromagnetic insulator state. This transition is related to the formation of short range charge/orbitally orde…
LOCAL-MOMENT AND ITINERANT ANTIFERROMAGNETISM IN THE HEAVY-FERMION SYSTEM CE(CU1-XNIX)2GE2
1992
Elastic and inelastic neutron-scattering studies on the system Ce(Cu1−xNix)2Ge2 are reported. These measurements are complemented by measurements of the magnetic susceptibility, high-field magnetization, heat capacity, thermal expansion, electrical resistivity and thermopower. The results reveal an interesting T-x phase diagram consisting of two different antiferromagnetic phases for x 0.5. Further experimental evidence for different types of antiferromagnetic ordering derives from a line-shape analysis of the quasielastic neutron-scattering intensity, from magnetization and thermopower experiments.
Low-temperature growth of n ++-GaN by metalorganic chemical vapor deposition to achieve low-resistivity tunnel junctions on blue light emitting diodes
2018
We report on low-resistivity GaN tunnel junctions (TJ) on blue light-emitting diodes (LEDs). Si-doped n ++-GaN layers are grown by metalorganic chemical vapor deposition directly on LED epiwafers. Low growth temperature (<800 °C) was used to hinder Mg-passivation by hydrogen in the p ++-GaN top surface. This allows achieving low-resistivity TJs without the need for post-growth Mg activation. TJs are further improved by inserting a 5 nm thick In0.15Ga0.85N interlayer (IL) within the GaN TJ thanks to piezoelectric polarization induced band bending. Eventually, the impact of InGaN IL on the internal quantum efficiency of blue LEDs is discussed.
The ultrafast dynamics and conductivity of photoexcited graphene at different Fermi energies
2017
The ultrafast dynamics and conductivity of photoexcited graphene can be explained using solely electronic effects.
On the Phase Separation in n-Type Thermoelectric Half-Heusler Materials
2018
Half-Heusler compounds have been in focus as potential materials for thermoelectric energy conversion in the mid-temperature range, e.g., as in automotive or industrial waste heat recovery, for more than ten years now. Because of their mechanical and thermal stability, these compounds are advantageous for common thermoelectric materials such as Bi 2 Te 3 , SiGe, clathrates or filled skutterudites. A further advantage lies in the tunability of Heusler compounds, allowing one to avoid expensive and toxic elements. Half-Heusler compounds usually exhibit a high electrical conductivity σ , resulting in high power factors. The main drawback of half-Heusler compounds is their high lattice th…
Impedance characterization of the electrochemical environment under a polymer film artificially delaminated
2008
International audience; Knowledge of the electrical conductivity of the zone under a delaminated paint film is one necessary input parameter for the simulation of electrochemically driven underpaint corrosion. In this work, a microelectrode array system has been developed, tested, and applied to measure the spatial distribution of resistivity in the delaminated zone along the metal/polymer interface. The experimental device consists of a linear array of six 100 m diameter stainless steel microelectrodes (100 m in diameter) embedded in a steel substrate. A polymer coatingwas applied and an artificial "delaminated zone"was created using the laser-induced decohesion technique. The electrochemi…
Light absorption and electrical transport in Si:O alloys for photovoltaics
2010
Thin films (100-500 nm) of the Si:O alloy have been systematically characterized in the optical absorption and electrical transport behavior, by varying the Si content from 43 up to 100 at. %. Magnetron sputtering or plasma enhanced chemical vapor deposition have been used for the Si:O alloy deposition, followed by annealing up to 1250 °C. Boron implantation (30 keV, 3-30× 1014 B/cm2) on selected samples was performed to vary the electrical sheet resistance measured by the four-point collinear probe method. Transmittance and reflectance spectra have been extracted and combined to estimate the absorption spectra and the optical band gap, by means of the Tauc analysis. Raman spectroscopy was …