scholarly journals Thermo-Electrical Conduction of the 2,7-Di([1,1′-Biphenyl]-4-yl)-9H-Fluorene Molecular System: Coupling between Benzene Rings and Stereoelectronic Effects

Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3215 ◽  
Author(s):  
Judith Helena Ojeda Silva ◽  
Juan Sebastián Paez Barbosa ◽  
Carlos Alberto Duque Echeverri
Keyword(s):  
Electrical Transport ◽  
Quantum Noise ◽  
Molecular System ◽  
Tight Binding ◽  
Electrical Conductance ◽  
Thermal Conductance ◽  
Fano Factor ◽  
Aromatic System ◽  
Electrical Transport Properties ◽  
Benzene Rings

Theoretical and analytical thermal and electrical properties are studied through the 2,7-Di([1,1′-biphenyl]-4-yl)-9H-fluorene aromatic system as a prototype of a molecular switch. Variations of the dihedral angles between the two Benzene rings at each end of the molecule have been considered, thus determining the dependence on the structural variation of the molecule when the aromatic system is connected between metal contacts. The molecule is modeled through a Tight-Binding Hamiltonian where—from the analytical process of decimation and using Green’s functions—the probability of transmission (T) is calculated by using the Fisher–Lee relationship. Consequently, the thermal and electrical transport properties such as I − V curves, quantum noise (S), Fano factor (F), electrical conductance (G), thermal conductance ( κ ), Seebeck coefficient (Q), and merit number ( Z T ) are calculated. The available results offer the possibility of designing molecular devices, where the change in conductance or current induced by a stereoelectronic effect on the molecular junctions (within the aromatic system) can produce changes on the insulating–conductive states.

Electrical Transport Properties of Carbon Nanotube Metal-Semiconductor Heterojunction

2016 ◽  
Vol 15 (05n06) ◽  
pp. 1660009 ◽  
Author(s):  
Keka Talukdar ◽  
Anil Shantappa
Keyword(s):  
Electrical Transport ◽  
Nearest Neighbor ◽  
Electronic Devices ◽  
Tight Binding ◽  
Transmission Function ◽  
Topological Defects ◽  
Dynamics Simulation ◽  
Internal Stresses ◽  
Electrical Transport Properties ◽  
Tight Binding Approximation

Carbon nanotubes (CNTs) have been proved to have promising applicability in various fields of science and technology. Their fascinating mechanical, electrical, thermal, optical properties have caught the attention of today’s world. We have discussed here the great possibility of using CNTs in electronic devices. CNTs can be both metallic and semiconducting depending on their chirality. When two CNTs of different chirality are joined together via topological defects, they may acquire rectifying diode property. We have joined two tubes of different chiralities through circumferential Stone–Wales defects and calculated their density of states by nearest neighbor tight binding approximation. Transmission function is also calculated to analyze whether the junctions can be used as electronic devices. Different heterojunctions are modeled and analyzed in this study. Internal stresses in the heterojunctions are also calculated by molecular dynamics simulation.

Electromechanical Behavior of Single and Multiwall Carbon Nanotubes

2008 ◽  
Vol 54 ◽  
pp. 390-395
Author(s):  
Antonio Pantano
Keyword(s):  
Carbon Nanotubes ◽  
Finite Element ◽  
Electrical Transport ◽  
Mixed Finite Element ◽  
Tight Binding ◽  
Multiwall Carbon Nanotubes ◽  
Building Blocks ◽  
Electrical Transport Properties ◽  
Electromechanical Behavior ◽  
Structural Deformations

Carbon nanotubes (CNTs) can be metallic or semiconductors depending simply on geometric characteristics. This peculiar electronic behavior, combined with high mechanical strength, make them potential building blocks of a new nano-electronic technology. High resolution images of CNTs often disclose structural deformations such as bent, twisted, or collapsed tubes. These deformations break the tube symmetry, and a change in their electronic properties should result. A computationally effective mixed finite element-tight-binding approach able to simulate the electromechanical behavior of single and multiwall nanotubes used in nano-electronic devices is presented. The finite element (FE) computes the evolution of atomic coordinates with deformation and provides these coordinates to a tight-binding (TB) code, enabling computation and updating of the electrical conductivity. The TB code is engineered to realize dramatic computational savings in calculating deformation-induced changes in electrical transport properties of the nanotubes.

scholarly journals Gold Nanoparticle-Mediated Noncovalent Functionalization of Graphene for Field-Effect Transistor

2021 ◽  
Author(s):  
Dongha Shin ◽  
Hwa Rang Kim ◽  
Byung Hee Hong
Keyword(s):  
Transport Properties ◽  
Gold Nanoparticle ◽  
Electrical Transport ◽  
Field Effect ◽  
High Performance ◽  
Field Effect Transistor ◽  
Electrical Transport Properties ◽  
Noncovalent Functionalization ◽  
Effect Transistor

Since of its first discovery, graphene has attracted much attention because of the unique electrical transport properties that can be applied to high-performance field-effect transistor (FET). However, mounting chemical functionalities...

scholarly journals Pressure-Induced Structural Phase Transition and Metallization in Ga2Se3 up to 40.2 GPa under Non-Hydrostatic and Hydrostatic Environments

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 746
Author(s):  
Meiling Hong ◽  
Lidong Dai ◽  
Haiying Hu ◽  
Xinyu Zhang
Keyword(s):  
Phase Transition ◽  
Electrical Conductivity ◽  
High Pressure ◽  
Phase Transformation ◽  
Transport Properties ◽  
Electrical Transport ◽  
Structural Phase ◽  
Structure Evolution ◽  
Systematic Research ◽  
Electrical Transport Properties

A series of investigations on the structural, vibrational, and electrical transport characterizations for Ga2Se3 were conducted up to 40.2 GPa under different hydrostatic environments by virtue of Raman scattering, electrical conductivity, high-resolution transmission electron microscopy, and atomic force microscopy. Upon compression, Ga2Se3 underwent a phase transformation from the zinc-blende to NaCl-type structure at 10.6 GPa under non-hydrostatic conditions, which was manifested by the disappearance of an A mode and the noticeable discontinuities in the pressure-dependent Raman full width at half maximum (FWHMs) and electrical conductivity. Further increasing the pressure to 18.8 GPa, the semiconductor-to-metal phase transition occurred in Ga2Se3, which was evidenced by the high-pressure variable-temperature electrical conductivity measurements. However, the higher structural transition pressure point of 13.2 GPa was detected for Ga2Se3 under hydrostatic conditions, which was possibly related to the protective influence of the pressure medium. Upon decompression, the phase transformation and metallization were found to be reversible but existed in the large pressure hysteresis effect under different hydrostatic environments. Systematic research on the high-pressure structural and electrical transport properties for Ga2Se3 would be helpful to further explore the crystal structure evolution and electrical transport properties for other A2B3-type compounds.

scholarly journals Structure, Morphology, Heat Capacity, and Electrical Transport Properties of Ti3(Al,Si)C2 Materials

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3222
Author(s):  
Kamil Goc ◽  
Janusz Przewoźnik ◽  
Katarzyna Witulska ◽  
Leszek Chlubny ◽  
Waldemar Tokarz ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Heat Capacity ◽  
Specific Heat ◽  
Electrical Transport ◽  
Residual Resistivity ◽  
Max Phase ◽  
Electrical Transport Properties ◽  
Debye Temperatures ◽  
Si Content ◽  
Hot Pressing Sintering

A study of Ti3Al1−xSixC2 (x = 0 to x = 1) MAX-phase alloys is reported. The materials were obtained from mixtures of Ti3AlC2 and Ti3SiC2 powders with hot pressing sintering technique. They were characterised with X-ray diffraction, heat capacity, electrical resistivity, and magnetoresistance measurements. The results show a good quality crystal structure and metallic properties with high residual resistivity. The resistivity weakly varies with Si doping and shows a small, positive magnetoresistance effect. The magnetoresistance exhibits a quadratic dependence on the magnetic field, which indicates a dominant contribution from open electronic orbits. The Debye temperatures and Sommerfeld coefficient values derived from specific heat data show slight variations with Si content, with decreasing tendency for the former and an increase for the latter. Experimental results were supported by band structure calculations whose results are consistent with the experiment concerning specific heat, resistivity, and magnetoresistance measurements. In particular, they reveal that of the s-electrons at the Fermi level, those of Al and Si have prevailing density of states and, thus predominantly contribute to the metallic conductivity. This also shows that the high residual resistivity of the materials studied is an intrinsic effect, not due to defects of the crystal structure.

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