Relaxation of highly excited carriers in wide-gap semiconductors

Tyuterev, V. G.; Zhukov, V. P.; Echenique, Pedro M.; Chulkov, Eugene V.

doi:10.1088/0953-8984/27/2/025801

Cited by 4 publications

(4 citation statements)

References 25 publications

(67 reference statements)

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“…The knowledge of the probabilities of electron scattering by short-wavelength phonons is necessary in the study of energy relaxation at high excitation levels by external high-energy radiation [18], as well as in connection with the search of thermoelectric materials with high efficiency [16], sf also recent review article Sjakste et al [47] and references therein.…”

Section: Discussionmentioning

confidence: 99%

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First-principle Calculations of Electron-Phonon Interactions in $A^{II}B^{IV}C^{V}_2$ Crystals

Tyuterev

2019

Preprint

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Ab − initio probabilities of phonon-assisted intervalley scattering of electrons in the conduction bands of ternary chalcopyrite compounds ZnSiP 2 and ZnGeP 2 between the central Γ minima and the lowest lateral minima (valleys) at T and N points have been calculated using the density functional theory. The equilibrium parameters of crystal structures, spectra of electrons and phonons are calculated self-consistently and are in fairly good agreement with the experiment and available theoretical calculations. The electron-phonon coupling constants with short-wave (inter-valley) phonons in the chalcopyrite phosphides are close to their values in Si, Ge and in binary analog GaP .

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Section: Discussionmentioning

confidence: 99%

“…Scattering of electrons by long-wave phonons in chalcopyrites earlier was studied in our paper [17]. In the presence of closely spaced energy minima in the conduction band the intervalley scattering (scattering by short-wavelength phonons) is also important, especially for the study of energy relaxation at high excitation levels [18].…”

Section: Introductionmentioning

confidence: 99%

First-principle Calculations of Electron-Phonon Interactions in $A^{II}B^{IV}C^{V}_2$ Crystals

Tyuterev

2019

Preprint

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“…However, one should expect that the recombination time is going to be several orders of magnitude smaller if there is no gap between the vacancy states and the conduction band, as is the cases for TiO 2 + vacancy and TiO 2 + N + vacancy. It was shown in [34] that, because of the emission of phonons, the excited electrons in the conduction band states of TiO 2 lose their excitation energy and sink onto the bottom of the band over the time that does not exceed several tens of fs; after this time the electrons recombine with the holes in the vacancy states. These data are also in agreement with the experimental results which reveal that the trapping of conduction band electron onto the states of dopants near the top of the band gap occurs over 100 -250 fs, while the hole trapping on the states near the bottom of the gap takes 50 -150 fs [33].…”

Section: Oxygen Vacancy Formation Energy and The Effect Of Doping Witmentioning

confidence: 99%

“…Therefore, one can expect that for these cases, only a small number of electrons are involved in the photocatalytic process. These are the excited electrons which form a high-energy "tail" of the electron distribution in the conduction band [34]; in analogy, a similar distribution of holes inside the valence band can exist [35]. In both cases, as in TiO 2 + vacancy as in TiO 2 + N + vacancy, the electron-hole pairs can be formed not only because of the excitations inside the conduction band but also because of the excitations into the conduction band from the valence band or from the band of nitrogen states.…”

Section: Oxygen Vacancy Formation Energy and The Effect Of Doping Witmentioning

confidence: 99%

Influence of carbon or nitrogen dopants on the electronic structure, optical properties and photocatalytic activity of partially reduced titanium dioxide

Zhukov¹,

Kostenko²,

Rempel³

et al. 2019

Nanosystems: Phys. Chem. Math.

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For titanium dioxide with anatase structure doped with carbon or nitrogen, the first-principle method of projector augmented waves (PAW) is used to calculate electronic band structure, to evaluate vacancy formation energy for the oxygen sublattice, and to analyze optical absorption. It is demonstrated that the presence of carbon dopants results in the stabilization of oxygen vacancies and leads to increased absorption in the visible spectrum, which can facilitate the photocatalytic activity. The presence of nitrogen dopant also facilitates vacancy stabilization but no increase in the interband absorption is expected in the visible spectrum, i.e., the presence of nitrogen dopant cannot be considered as a factor contributing to increased photocatalytic activity. It follows from the calculated data that the maximum photocatalytic activity should be expected for the partiallyreduced anatase doped with carbon because of the absorption in the visible spectrum that combines with long time of electron-hole recombination.

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Electron-phonon relaxation and excited electron distribution in gallium nitride

Zhukov

Tyuterev

Chulkov

et al. 2016

Journal of Applied Physics

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Abstract. We develop a theory of energy relaxation in semiconductors and insulators highly excited by the long-acting external irradiation. We derive the equation for the non-equilibrium distribution function of excited electrons. The solution for this function breaks up into the sum of two contributions. The low-energy contribution is concentrated in a narrow range near the bottom of the conduction band. It has the typical form of a Fermi distribution with an effective temperature and chemical potential. The effective temperature and chemical potential in this lowenergy term are determined by the intensity of carriers' generation, the speed of electron-phonon relaxation, rates of inter-band recombination and electron capture on the defects. In addition, there is a substantial high-energy correction. This high-energy 'tail' covers largely the conduction band. The shape of the highenergy 'tail' strongly depends on the rate of electron-phonon relaxation but does not depend on the rates of recombination and trapping. We apply the theory to the calculation of a non-equilibrium distribution of electrons in irradiated GaN. Probabilities of optical excitations from the valence to conduction band and electronphonon coupling probabilities in GaN were calculated by the density functional perturbation theory. Our calculation of both parts of distribution function in gallium nitride shows that when the speed of electron-phonon scattering is comparable with the rate of recombination and trapping then the contribution of the non-Fermi 'tail' is comparable with that of the low-energy Fermi-like component. So the high-energy contribution can affect essentially the charge transport in the irradiated and highly doped semiconductors.

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Relaxation of highly excited carriers in wide-gap semiconductors

Cited by 4 publications

References 25 publications

First-principle Calculations of Electron-Phonon Interactions in $A^{II}B^{IV}C^{V}_2$ Crystals

First-principle Calculations of Electron-Phonon Interactions in $A^{II}B^{IV}C^{V}_2$ Crystals

Influence of carbon or nitrogen dopants on the electronic structure, optical properties and photocatalytic activity of partially reduced titanium dioxide

Electron-phonon relaxation and excited electron distribution in gallium nitride

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