Electrical transport and band structure of GaAs

1979 ◽  
Vol 57 (2) ◽  
pp. 233-242 ◽  
Author(s):  
H. J. Lee ◽  
J. Basinski ◽  
L. Y. Juravel ◽  
J. C. Woolley
Keyword(s):  
Experimental Data ◽  
Electrical Conductivity ◽  
Band Structure ◽  
Hall Coefficient ◽  
Electrical Transport ◽  
Theoretical Calculations ◽  
Deformation Potential ◽  
Coupling Coefficients ◽  
Band Energy ◽  
Temperature Coefficients

Measurements of electrical conductivity σ and Hall coefficient RH have been made as a function of temperature in the range room to 500 °C on single crystal n-type tellurium doped samples of GaAs with carrier concentrations in the range 7.9 × 1021 to 4.7 × 1024/m3. Theoretical calculations of σ and RH have been made on a three band (Γ, L, X) model using the method of Fletcher and Butcher and the resulting values fitted to the experimental data by using the temperature coefficients of the band energy differences and various deformation potentials and band coupling coefficients as adjustable parameters. The results confirm the band ordering proposed by Aspnes but give slightly different temperature coefficient values. Values are given for the deformation potentials and band coupling coefficients and in particular the deformation potential of the Γ band is found to be 16.0 ± 0.5 eV.

EFFECTIVE MOBILITY MODEL OF GRAPHENE NANORIBBON IN PARABOLIC BAND ENERGY

2011 ◽  
Vol 25 (10) ◽  
pp. 739-745 ◽  
Author(s):  
N. A. AMIN ◽  
M. T. AHMADI ◽  
Z. JOHARI ◽  
S. M. MOUSAVI ◽  
R. ISMAIL
Keyword(s):  
Experimental Data ◽  
Band Structure ◽  
Transport Properties ◽  
Conventional Method ◽  
Dirac Point ◽  
Graphene Nanoribbons ◽  
Mobility Model ◽  
Band Energy ◽  
One Dimensional ◽  
Effective Mobility

In this letter, we investigate the transport properties of one-dimensional semiconducting Graphene nanoribbons (GNRs) with parabolic band structure near the Dirac point. The analytical model of effective mobility is developed by using the conductance approach, which differs from the conventional method of extracting the effective mobility using the well-known Matthiessen rule. Graphene nanoribbons conductance model developed was applied in the Drude model to obtain the effective mobility, which then gives nearly close comparison with the experimental data.

Computational Analysis of Strain Effects on Electrical Transport Properties of Crystalline Nanocomposite Thin Films

2011 ◽  
Author(s):  
Hua Li ◽  
Gang Li
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Band Structure ◽  
Transport Properties ◽  
Electrical Transport ◽  
Electronic Band Structure ◽  
Electrical Transport Properties ◽  
Electronic Band ◽  
Strain Effects ◽  
Nanocomposite Thin Films

In this work, we model the strain effects on the electrical transport properties of Si/Ge nanocomposite thin films. We utilize a two-band k·p theory to calculate the variation of the electronic band structure as a function of externally applied strains. By using the modified electronic band structure, electrical conductivity of the Si/Ge nanocomposites is calculated through a self-consistent electron transport analysis, where a nonequilibrium Green’s function (NEGF) is coupled with the Poisson equation. The results show that both the tensile uniaxial and biaxial strains increase the electrical conductivity of Si/Ge nanocomposite. The effects are more evident in the biaxial strain cases.

Partial Carbonization of Aromatic Polyimide Films

1999 ◽  
Vol 593 ◽  
Author(s):  
M. Doyama ◽  
A. Ichida ◽  
Y. Inoue ◽  
Y. Kogure ◽  
T. Nozaki ◽  
...  
Keyword(s):  
Experimental Data ◽  
Electrical Conductivity ◽  
Hall Coefficient ◽  
Carrier Density ◽  
Carrier Mobility ◽  
Absolute Temperature ◽  
Polyimide Films ◽  
Aromatic Polyimide ◽  
The Absolute

ABSTRACTAromatic polyimide films are partially carbonized between 700°C and 1000°C. Electrical conductivity and Hall coeficient have been measured. Electrical conductivity is higher at higher measuring temperatures. The electrical conductivity σ can be expressed as σ= σ0exp (–E /kT), where k is the Boltzman constant. T is the absolute temperature. E depends upon the carborized temperature. The experimental data show the Hall coefficient RH is negative, and this implies the carriers are negatively charged, i.e. electrons. The specimens are n-type semiconductors. The carrier density η can be expressed by η= A1 exp (–E1/κT) and carrier mobility μ can be expressed by μ = A1exp ( E2/κT). E, E1andE2 depend upon the carbonized temperature

Conduction bands of GaxIn1−xAs and InAsxSb1−xalloys

1970 ◽  
Vol 48 (4) ◽  
pp. 463-469 ◽  
Author(s):  
William M. Coderre ◽  
John C. Woolley
Keyword(s):  
Electrical Conductivity ◽  
Band Structure ◽  
Valence Band ◽  
Conduction Band ◽  
High Temperatures ◽  
Hall Coefficient ◽  
Solidus Temperature ◽  
Energy Separation ◽  
Conduction Bands ◽  
Valence Bands

Measurements of Hall coefficient and electrical conductivity have been made on alloys of the systems GaxIn1−xAs and InAsxSb1−xover a range of temperature from 200 up to 950 °K or to 20° below the solidus temperature of the particular specimen, whichever was lower. These data have then been analyzed in terms of equations involving all the occupied conduction and valence bands in the manner described previously by Coderre and Woolley. The results give the variation of the energy separation from the valence band of the (000) conduction-band minimum as a function of the composition and temperature for both alloy systems. For a certain range of x in the InAsxSb1−x alloys, a transition to the gray-tin band structure is observed at high temperatures.

Drift mobility and Hall coefficient factor of holes in germanium and silicon

1978 ◽  
Vol 56 (3) ◽  
pp. 364-372 ◽  
Author(s):  
H. Nakagawa ◽  
S. Zukotynski
Keyword(s):  
Experimental Data ◽  
Band Structure ◽  
Hall Coefficient ◽  
Phonon Scattering ◽  
Impurity Scattering ◽  
Drift Mobility ◽  
Structure Model ◽  
Optical Phonon Scattering ◽  
Band Structure Model ◽  
Good Agreement

The drift mobility and the Hall coefficient factor are calculated using the Kane band structure model without approximations. Acoustic and optical phonon scattering and also impurity scattering are considered. The effects of light and heavy holes on the drift and the Hall mobility are discussed. The results for the drift mobility agree with experimental data both for Ge and Si. The results for the Hall coefficient factor are in good agreement for Si, but in the case of Ge, the agreement is only fair.

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.

Dual percolations of electrical conductivity and electromagnetic interference shielding in progressively agglomerated CNT/polymer nanocomposites

2021 ◽  
pp. 108128652110214
Author(s):  
Xiaodong Xia ◽  
George J. Weng
Keyword(s):  
Experimental Data ◽  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Percolation Threshold ◽  
Polymer Nanocomposites ◽  
Electromagnetic Interference ◽  
Effective Medium Theory ◽  
Scale Model ◽  
Shielding Effectiveness ◽  
Emi Shielding

Recent experiments have revealed two distinct percolation phenomena in carbon nanotube (CNT)/polymer nanocomposites: one is associated with the electrical conductivity and the other is with the electromagnetic interference (EMI) shielding. At present, however, no theories seem to exist that can simultaneously predict their percolation thresholds and the associated conductivity and EMI curves. In this work, we present an effective-medium theory with electrical and magnetic interface effects to calculate the overall conductivity of a generally agglomerated nanocomposite and invoke a solution to Maxwell’s equations to calculate the EMI shielding effectiveness. In this process, two complex quantities, the complex electrical conductivity and complex magnetic permeability, are adopted as the homogenization parameters, and a two-scale model with CNT-rich and CNT-poor regions is utilized to depict the progressive formation of CNT agglomeration. We demonstrated that there is indeed a clear existence of two separate percolative behaviors and showed that, consistent with the experimental data of poly-L-lactic acid (PLLA)/multi-walled carbon nanotube (MWCNT) nanocomposites, the electrical percolation threshold is lower than the EMI shielding percolation threshold. The predicted conductivity and EMI shielding curves are also in close agreement with experimental data. We further disclosed that the percolative behavior of EMI shielding in the overall CNT/polymer nanocomposite can be illustrated by the establishment of connective filler networks in the CNT-poor region. It is believed that the present research can provide directions for the design of CNT/polymer nanocomposites in the EMI shielding components.

Cross sections for d-3H neutron interactions with samarium isotopes

2016 ◽  
Vol 104 (8) ◽  
Author(s):  
Junhua Luo ◽  
Chunlei Wu ◽  
Li Jiang ◽  
Long He
Keyword(s):  
Experimental Data ◽  
Neutron Flux ◽  
Cross Sections ◽  
Theoretical Calculations ◽  
Nuclear Model ◽  
Activation Technique ◽  
Incident Neutron ◽  
Reaction Threshold ◽  
Talys 1.6 ◽  
The Cross

Abstract:The cross sections for (n,x) reactions on samarium isotopes were measured at (d-T) neutron energies of 13.5 and 14.8 MeV with the activation technique. Samples were activated along with Nb and Al monitor foils to determine the incident neutron flux. Theoretical calculations of excitation functions were performed using the nuclear model codes TALYS-1.6 and EMPIRE-3.2 Malta with default parameters, at neutron energies varying from the reaction threshold to 20 MeV. The results were discussed and compared with experimental data found in the literature. At neutron energies 13.5 and 14.8 MeV, the cross sections of the

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