Energy Spectrum Of Holes Research Articles

Single nucleation of Cl-doped FAPbBr3 with inhibited ion migration for ambipolar radiation detection

High-quality and dopant-compensated FAPbBr3−xClx single crystals were demonstrated. The as-grown FAPbBr2.9Cl0.1 prevented halide migration appreciably and exhibited well-defined α-particle energy spectra of both electrons and holes.

To the Theory of Dimensional Quantization in Narrow-Gap Crystals

This article discusses studies of size quantization phenomena in zero-, one-, and two-dimensional semiconductor structures. The main attention is paid to the mechanisms of photon-kinetic effects in these structures. Despite many studies of the physical properties of low-dimensional systems of current carriers, the size quantization of energy spectra in narrow-gap semiconductors and the associated photonic-kinetic effects are still insufficiently studied. Therefore, this study focuses on the quantum mechanical study of size quantization in certain cases using Kane's multiband model. The insolvability of the 8×8 matrix Schrödinger equation in the Kane model for a potential well of arbitrary shape is analyzed. The dependence of the energy spectrum on the two-dimensional wave vector is studied for various cases. In particular, the energy spectra for InSb and GaAs semiconductors are considered, depending on the band parameters and the size of the potential well. Conclusions are presented on the analysis of various cases of size quantization in narrow-gap crystals with cubic or tetrahedral symmetry in the three-band approximation. It is shown that the energy spectrum corresponds to a set of size-quantized levels that depend on the Rabi parameter, band gap, and well size. The size-quantized energy spectra of electrons and holes in InSb and GaAs semiconductors are analyzed in a multiband model.

Quantization of the Energy Spectrum of Holes in the Adiabatic Potential of the Electron

The spectra of the interband absorption of microscopic CdS crystals, 15 to 30 Å in size, grown in a transparent insulating matrix, are analyzed. A structural feature caused by quantization of the energy spectrum of the hole in the adiabatic potential of its Coulomb interaction with the electron has been detected near the transitions to the lower level of the size quantization of the electron.

Unveiling the Role of Donor Impurity Position on the Electronic Properties in Strained Type I and Type II Core/Shell Quantum Dots under Magnetic Field.

In this theoretical investigation, we delve into the significant effects of donor impurity position within core/shell quantum dot structures: type I (CdTe/ZnS) and type II (CdTe/CdS). The donor impurity's precise location within both the core and the shell regions is explored to unveil its profound influence on the electronic properties of these nanostructures. Our study investigates the diamagnetic susceptibility and binding energy of the donor impurity while considering the presence of an external magnetic field. Moreover, the lattice mismatch-induced strain between the core and shell materials is carefully examined as it profoundly influences the electronic structure of the quantum dot system. Through detailed calculations, we analyze the strain effects on the conduction and valence bands, as well as the electron and hole energy spectrum within the core/shell quantum dots. The results highlight the significance of donor impurity position as a key factor in shaping the behaviors of impurity binding energy and diamagnetic susceptibility. Furthermore, our findings shed light on the potential for tuning the electronic properties of core/shell quantum dots through precise impurity positioning and strain engineering.

Энергетический спектр и волновые функции дырок в 2D-сверхрешетках из квантовых проволок (GaAs/AlAs)

A numerical analysis of the hole energy spectrum and wave functions in a 2D (GaAs/AlAs) quantum wire (QWr) superlattice (SL) with arbitrary cross-section is presented. The intricate fourfold degenerate nature of valence band Г8 of the given materials is taken into account. The presented approach is based on a modified effective mass method, wherein the microscopic structure of the heterostructure and hole kp-interaction in the valence band are considered. It is shown that the solution of this problem in a k-representation is reduced to an eigenvalue problem for a matrix Hamiltonian. Superlattices of quantum wires with different cross-sections (square, circle, ellipse, and ring) are considered as an example. The influence of superlattice parameters on the hole energy spectrum is studied. Anti-crossing effects in the hole dispersion law are observed. For the hole ground and excited states, the wave function spatial distribution in the plane perpendicular to the QWr axis is also studied.

Novel InGaSb/AlP Quantum Dots for Non-Volatile Memories.

Non-volatile memories based on the flash architecture with self-assembled III-V quantum dots (SAQDs) used as a floating gate are one of the prospective directions for universal memories. The central goal of this field is the search for a novel SAQD with hole localization energy (Eloc) sufficient for a long charge storage (10 years). In the present work, the hole states' energy spectrum in novel InGaSb/AlP SAQDs was analyzed theoretically with a focus on its possible application in non-volatile memories. Material intermixing and formation of strained SAQDs from a GaxAl1-xSbyP1-y, InxAl1-xSbyP1-y or an InxGa1-xSbyP1-y alloy were taken into account. Critical sizes of SAQDs, with respect to the introduction of misfit dislocation as a function of alloy composition, were estimated using the force-balancing model. A variation in SAQDs' composition together with dot sizes allowed us to find that the optimal configuration for the non-volatile memory application is GaSbP/AlP SAQDs with the 0.55-0.65 Sb fraction and a height of 4-4.5 nm, providing the Eloc value of 1.35-1.50 eV. Additionally, the hole energy spectra in unstrained InSb/AlP and GaSb/AlP SAQDs were calculated. Eloc values up to 1.65-1.70 eV were predicted, and that makes unstrained InGaSb/AlP SAQDs a prospective object for the non-volatile memory application.

Two-body Wigner molecularization in asymmetric quantum dot spin qubits

Coulomb interactions strongly influence the energy spectrum and wave functions of few electrons or holes in single quantum dots. Indeed, for weak confinement potentials, the Coulomb repulsion splits apart the particles, leading to the formation of Wigner molecules. Here, the authors discuss how the confinement anisotropy favors the molecularization and compare the impact on readout and exchange interactions for spin qubits in different semiconductor materials.

ВЫЧИСЛЕНИЕ ТЕМПЕРАТУРНОЙ ЗАВИСИМОСТИ ЭНЕРГЕТИЧЕСКОГО СПЕКТРА НОСИТЕЛЕЙ ЗАРЯДОВ В ПОЛУПРОВОДНИКАХ ПРИ ВОЗДЕЙСТВИИ СИЛЬНОГО МАГНИТНОГО ПОЛЯ

The energy spectrum of free holes in a st rong magnetic field is calculated for a non- quadratic dispersion law. The temperature dependen ce of the broadening of the Landau levels of holes in crystals with the Kane dispersion law has been studied. A new method for calculating the discrete energy spectrum in a quantizing magnetic field is proposed

Фотопроводимость и поглощение инфракрасного излучения в квантовых ямах p-GaAs/AlGaAs

The spectra of low-temperature impurity-assisted far and mid-infrared photoconductivity and absorption in nanostructure with multiple GaAs/AlGaAs quantum wells doped with acceptors are investigated. The experimentally obtained absorption and photoconductivity spectra correlate well with each other. According to the hole and acceptor state energy spectrum calculations the spectral features related to the optical hole transitions from the ground acceptor state to the delocalized states of valence subbands, to the excited acceptor states and to the delocalized states above the quantum well (photoionization) are identified in the absorption and photoconductivity spectra.

On Heating and Relaxation of the Electron—Hole-Gas Energy in the Track of a Primary Recoil Atom

On the basis of the Monte Carlo algorithm, a method for calculating the energy spectrum of hot nonequilibrium electrons and holes in the track of a primary recoil atom after being exposed to single fast neutrons is developed. The heating and subsequent relaxation of nonequilibrium charge carriers in silicon in the track of a charged particle with initial energies in the range of 50–200 keV are calculated. The characteristic temperatures of the electron and hole plasma are obtained, which amount to 5400 and 2700 K, respectively. The effect of the radiation-induced heating of charge carriers on the failure stability of static memory cells is discussed.

Effect of design and stress relaxation on structural, electronic, and luminescence properties of metamorphic InAs(Sb)/In(Ga,Al)As/GaAs mid-IR emitters with a superlattice waveguide

We report on structural and optical studies of metamorphic InAs(Sb)/In(Ga,Al)As quantum well (QW) heterostructures with different designs of the active region, grown by molecular beam epitaxy on GaAs substrates and emitting in the mid-IR spectral range (3.0–3.5 μm) at room temperature. The influence of the thickness of the InGaAs/InAlAs superlattice waveguide and design of the InSb/InAs/InGaAs QW on stress balance in such metamorphic structures, their luminescent properties, and density of extended defects in the active region is discussed. The peculiarities of electron and hole energy spectra of the active region vs stress and design are studied theoretically in the framework of the 8-band Kane model and verified experimentally by Fourier-transform infrared photoreflectance spectroscopy. Despite that optimized metamorphic heterostructures are characterized by the extended defect density in the active region of just about 107 cm−2, carrier confinement in the QW has a stronger impact on their mid-IR photoluminescence intensity at room temperature.

The influence of acoustic deformation on the recombination radiation in InAs/GaAs heterostructure with InAs quantum dots

Abstract In the framework of electron-deformation model, the influence of deformation on the energy spectrum of electrons and holes in InAs/GaAs heterostructure with InAs quantum dots (QD) is investigated. The influence of acousto-electronic effects on the modulation of radiation energy at the recombination transition between the ground states of electron and hole in InAs/GaAs heterostructure with InAs quantum dots is investigated. The nature of the amplitude dependence of the modulation of the recombination radiation energy on the QD size and the amplitude of the mechanical stress created by the acoustic wave on the surface of the matrix is established.

Разогрев и релаксация энергии электронно-дырочного газа в треке первичного атома отдачи

Based on the Monte Carlo algorithm, a method has been developed for calculating the energy spectrum of hot nonequilibrium electrons and holes in the track of the primary recoil atom when exposed to single fast neutrons. The calculations of the heating and subsequent relaxation of nonequilibrium charge carriers in silicon in the track of a charged particle with initial energies in the range of 50...200 keV are carried out. The characteristic temperatures of the electron and hole plasma were obtained, which amounted to 5400 K and 2700 K, respectively. The effect of radiation-induced heating of charge carriers on the failure stability of static memory elements is discussed.

Hole States in Spherical Quantum Nanoheterosystem with Intermediate Spin-Orbital Interaction

The hole energy spectrum has been studied for the spherical semiconductor nanoheterosystem with the cubic symmetry. The exact solutions of the Schrödinger equation for the ground and excited hole states are presented within the framework of the 6-band Luttinger Hamiltonian and the finite gap of bands with the corresponding boundary conditions. Dependence of the holes energies from the radius of the quantum dot has been calculated for the GaAs/AlAs heterostructure. Obtained results where compared with data obtained using the infinite potential well model, as well as the single-band model for heavy and light holes.

Structure of the Energy Spectrum of Holes in IV–VI Materials from a Different Viewpoint

Structure of the Energy Spectrum of Holes in IV–VI Materials from a Different Viewpoint

The hole energy spectrum of an open spherical quantum dot within the multiband model

An open spherical quantum dot (OSQD) has been studied. The theory for calculation of the quasistationary hole states in the OSQD has been presented. The condition under which a OSQD turns into a closed spherical quantum dot (CSQD) is determined. Obtained results for the OSQD within the multiband model were compared with those of the single band model. The presented theory can be used to determine the decay time and line widths of the quasistationary hole states. Also it can be the basis to determine the acceptor states in the OSQD.

Energy Spectrum of Charge Carriers in Elastically Strained Assemblies of Ge/Si Quantum Dots

The results of studying the energy spectrum of electrons and holes localized in second-type Ge/Si heterostructures with Ge quantum dots are presented. In such structures, holes are localized at Ge quantum dots, and electrons, in three-dimensional quantum wells, which form in Si at the Ge—Si interface because of inhomogeneous deformations that appear as a result of the difference between the Ge and Si lattice constants. It is shown that changes in the deformations in the assembly of quantum dots as a result of a variation in their spatial arrangement significantly changes the binding energy of electrons, the position of their localization at quantum dots, the binding energy and wave-function symmetry of holes at double quantum dots (artificial molecules), and the exchange interaction of electrons and holes in the exciton composition. A practically important result of the presented data is the development of approaches to increase the luminescence quantum efficiency and the absorption coefficient in assemblies of quantum dots.

Miniband Electroconductivity in Superlattices of Cubic Quantum Dots of the InAs/GaxIn1-xAs Heterosystem

In this paper, the model of InAs/GaxIn1-xAs cubic quantum dot superlattices (CQDS) of various dimensionality has been proposed. The energy spectra of electrons and holes of the quantum dot superlattice have been determined in the effective mass approximation and modified Kronig-Penney model. In the frame of this model, the spectra of charges of 3D, 2D and 1D-superlattices can be obtained by changing respective distances between the elements of the superlattice. The energy dependence of the electron and hole subbands (under-the-barrier subbands and over-the-barrier subbands) on the wave vector of the superlattice has been calculated. The number of under-the-barrier subbands is determined by QD size and width of each subband is defined by QD size, distances between superlattice elements and subband numerical index.
 The dependences of the Fermi energy and concentration of charge carriers on temperature, concentration of impurities, energy of impurity levels have been obtained and analyzed. We have taken account of the dependence of electron relaxation time on temperature caused by scattering of carriers on both phonons and donor centers. The effect of the impurity system on electroconductivity of the CQDS is investigated.

Mechanisms of conductivity and energy spectrum of near-edge holes in Cu2ZnSnS4 powder samples

The resistivity, ρ(T), of Cu2ZnSnS4 powder samples, obtained by a solid-state reaction method from pure elements, exhibits an activated character. The Mott variable-range hopping charge transfer is observed between T ∼100–230 K, followed by the conductivity due to activation of holes into the states above the mobility threshold when T is increased. Such behavior, accompanied by semi-width W of the acceptor band, exceeding the mean acceptor energy, indicates overlap of the acceptor band states with those of the valence band, forming a joint near-edge hole spectrum in conditions of the strong degree of the compensation. The details of this spectrum have been determined, including positions of the Fermi level, μ, and the mobility threshold, as well as the density of the localized states at the Fermi level, g (μ). The acceptor concentration and the hole localization radius have been obtained, too. These parameters indicate the material to lie relatively far from the metal-insulator transition.

Energy spectrum of black holes: A new view

Energy of a black hole is usually quantized by invoking some area quantization scheme after expressing the energy in terms of the horizon area. However, in this approach one has to quantize the local and asymptotic energy of the black hole separately and the two results do not manifest any physical correspondence with each other. Here, as opposed to this practice, we find the unique energy spectrum of black holes by adopting a top-down approach. The physical links among the underlying quantum theory, statistical mechanics and thermodynamics of the black hole horizon play the central role in determining the energy spectrum. The energy spectrum that we obtain explicitly reveals the correspondence between asymptotic and local observations through the presence of the surface gravity of the horizon as a parameter in the spectrum, rather than being expressed as a function of area and consequently getting quantized in the usual approach. Thus, our result presents a new view as far as black hole energy quantization is concerned. The calculations are performed using the quantum geometric description of black hole horizons as laid down by loop quantum gravity.