Charge Carrier Scattering Research Articles

Scattering of Charge Carriers by Impurity Ions in InAs/AlSb Heterostructure

The mechanism of charge carrier scattering on ionized impurity atoms in an InAs/AlSb heterostructure with two filled size quantization subbands is studied. The purpose of the article is to develop a theory that fully describes quantum-mechanical processes in the structure under study. The calculation performed within the framework of the proposed transport time algorithm showed that the developed theory describes with high accuracy the mechanism of scattering of two-dimensional carriers by donor impurity ions in an active InAs layer. It was established that the lifetime limiting the mobility of two-dimensional carriers upon scattering by impurity ions is of the order of 10–12 s.

Magnetic Phase Transitions and the Anisotropy of Charge Carrier Scattering in Antiferromagnetic Metal Ho0.5Lu0.5B12 with Dynamic Charge Stripes

The transverse magnetoresistance, heat capacity, and magnetization of monodomain single crystals of dodecaboride Ho0.5Lu0.5B12 with a cage-glass structure are investigated at helium temperatures. It is shown that the anisotropy of charge carrier scattering in the antiferromagnetic phase is due to dynamic charge stripes oriented along directions 〈110〉 in the fcc lattice.

Extracting the Energy Sensitivity of Charge Carrier Transport and Scattering

It is a challenge to extract the energy sensitivity of charge carriers’ transport and scattering from experimental data, although a theoretical estimation in which the existing scattering mechanism(s) are preliminarily assumed can be easily done. To tackle this problem, we have developed a method to experimentally determine the energy sensitivities, which can then serve as an important statistical measurement to further understand the collective behaviors of multi-carrier transport systems. This method is validated using a graphene system at different temperatures. Further, we demonstrate the application of this method to other two-dimensional (2D) materials as a guide for future experimental work on the optimization of materials performance for electronic components, Peltier coolers, thermoelectricity generators, thermocouples, thermopiles, electrical converters and other conductivity and/or Seebeck-effect-related sensors.

Charge Carrier Scattering in Polymers: A New Neutral Coupled Soliton Channel

The dynamical scattering of two oppositely charged bipolarons in non-degenerate organic semiconducting lattices is numerically investigated in the framework of a one-dimensional tight-biding–Hubbard model that includes lattice relaxation. Our findings show that it is possible for the bipolaron pair to merge into a state composed of a confined soliton-antisoliton pair, which is characterized by the appearance of states within less than 0.1 eV from the Fermi level. This compound is in a narrow analogy to a meson confining a quark-antiquark pair. Interestingly, solitons are quasi-particles theoretically predicted to arise only in polymer lattices with degenerate ground state: in the general case of non-degenerate ground state polymers, isolated solitons are not allowed.

Magnetoresistance Scaling and the Anisotropy of Charge Carrier Scattering in the Paramagnetic Phase of Ho0.8Lu0.2B12 Cage Glass

The transverse magnetoresistance of Ho0.8Lu0.2B12 dodecaboride with a cage glass structure is studied at low (2–10 K) temperatures. It is demonstrated that the isotropic negative magnetoresistance in this antiferromagnet is dominant within the broad temperature range near TN ≈ K. This contribution to the total magnetoresistance is due to the scattering of charge carriers by nanoclusters formed by Но3+ ions, and it can be scaled in the ρ = f(μ2effH2/T2 ) representation. It is found that the magnetoresistance anisotropy above (about 15% at 80 kOe) is due to the positive contribution, which achieves maximum values at the magnetic field direction close to H ║ [001]. The anisotropy of the charge carrier scattering is interpreted in terms of the cooperative dynamic Jahn−Teller effect at В12 clusters.

Parameters of the Constant-Energy Surface and Features of Charge Carrier Scattering of Bi2Te3-Based Epitaxial Films

Galvanomagnetic properties of epitaxial Bi0.5Sb1.5Te3 films grown by the hot-wall technique were investigated in magnetic fields of H = 5 T to 14 T through the temperature interval of 10 K to 300 K. The results were analyzed in terms of a many-valley model of the energy spectrum and anisotropic charge carrier scattering. The degeneracy parameter βd, and ratios of components of the reciprocal effective-mass tensor \( {\mathord{\scriptscriptstyle\leftrightarrow}\over \alpha} \) and relaxation time tensor \( {\mathord{\scriptscriptstyle\leftrightarrow}\over \tau } (\varepsilon ) \) were estimated. Substantial anisotropy of charge carrier scattering was observed in the investigated temperature interval. Anisotropy of charge carrier scattering along bisector axes is enhanced, as compared with that of corresponding bulk samples. High charge carrier mobility and higher angular factor of the temperature dependence of mobility promote enhancement of the figure of merit Z of the films as compared with that of corresponding bulk solid solutions.

Total Ionizing Dose Induced Charge Carrier Scattering in Graphene Devices

We investigate total ionizing dose (TID) effects in graphene field effect transistors comprised of chemical vapor deposition grown graphene transferred onto trimethylsiloxy(TMS)-passivated SiO2 Si substrates. TID exposure with a positive gate bias increases the concentration of positive oxide trapped charges near the SiO2/TMS/graphene interface making Coulomb-potential scatterer limited mobility more apparent. In particular, we observe asymmetric degradation in electron and hole mobility, the former degrading more rapidly. Consistent with the electron-hole puddle description, we observe an increase in intrinsic electron carrier density that varies linearly with the oxide trapped charge density, while the hole carrier density remains largely unaltered. These effects give rise to an increasing minimum conductivity.

Scattering of charge carriers on a disordered atomic lattice of a P-type silicon isotropic polycrystal

A new mechanism of scattering of charge carriers in polycrystals is examined in the present paper. The polycrystal is a set of crystallites oriented arbitrarily relative to each other, which leads to the atomic lattice random in space and causes an additional mechanism of charge carrier scattering in the polycrystal. The mobility of charge carriers in the p-type silicon polycrystal is calculated and compared with the available experimental data.

Annealing Effect on Charge Carrier Scattering in Irradiated Silicon from Cyclotron Resonance Data

Annealing Effect on Charge Carrier Scattering in Irradiated Silicon from Cyclotron Resonance Data

Study of the Hall Coefficient in p‐Type Germanium Taking into Account Anisotropic Charge Carrier Scattering

AbstractA quasi‐momentum distribution function of light and heavy holes in p‐type Ge is found by expanding the field and the collision terms of the kinetic equation in terms of the anisotropy parameter, indicating the degree of non‐sphericity of constant energy surfaces, in the zeroth, first, and second order approximation. The above method for solving the kinetic equation enables one to calculate the magnetic field dependence of the Hall coefficient taking into account the complex structure of the valence band of p‐Ge and the nature of carrier scattering. The calculated RH/R0 = f(B) dependence is compared with the experimental values obtained on samples with p = 1.7 × 1014 cm−3 having an orientation E ∥ 〈100〉, B ∥ 〈001〉 for T = 77 and 300 K.

Investigation of the Charge Carrier Scattering in Bi under High Hydrostatic Pressure

AbstractA detailed and precise measurement is given of the temperature dependence of the electrical resistivity of bismuth in the temperature range 2 K < T < 77 K. Under high hydrostatic pressure the Fermi energy is varied over a wide range. From the obtained temperature dependence of the electrical resistivity – a linear dependence for temperatures > 20 K and a T2 dependence at lower temperatures – as well as the characteristic dependence of the strength of the linear and quadratic terms from the electron Fermi energy, it is suggested that at temperatures > 20 K the resistivity is dominated by electron–phonon scattering, however, at lower temperatures a contribution due to carrier–carrier scattering may be significant.

Charge Carrier Scattering on Neutral Centres in n‐Si

AbstractA discussion of the basic models for the calculation of the relaxation time for scattering on neutral impurities is given. A comparison is made between the experimental results of scattering of electrons on neutral oxygen atoms in n‐Si and the theoretical data obtained on the basis of three models. It is shown that an S‐partial wave approximation with a phase shift linear in the momentum, taking into account Friedel's sum rules and the many‐channel scattering in many‐valley semi‐conductors, gives a good agreement with experimental results for impurity concentrations from 1013 to 1017 cm−3 in the temperature interval 77 to 300 K.

Screening, Instability of the Uniform State, and Charge Carrier Scattering in Heavily Doped Ferromagnetic Semiconductors

AbstractA calculation of the static dielectric function ε(q) and the magnetic response function to an electrostatic perturbation χ(q) is carried out for heavily doped ferromagnetic semiconductors. Due to the spin polarization of the charge carrier a strong correlation exists between the fluctuations of electron density and magnetization. This leads to diminishing screening length and the appearance of local magnetic moments near impurities, which, in turn, causes a strong magnetic field and temperature dependence of the resistivity. On further temperature increase, the screened potential becomes oscillating, and the screening length increases, going to infinity at a temperature which corresponds to the absolute instability of the uniform state. But still earlier a first order phase transition should occur into a nonuniform state, the nonuniform state being metastable in some temperature range. It may be responsible for the resistivity hysteresis observed in some ferromagnetic semiconductors.