“Hot electrons in Si lose energy mostly to optical phonons”: Truth or myth?

Fischetti, Massimo V.; Yoder, P. Douglas; Khatami, Mohammad Mahdi; Gaddemane, Gautam; Put, Maarten L. Van de

doi:10.1063/1.5099914

Cited by 19 publications

(21 citation statements)

References 62 publications

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“…In the interpolation, random grids of 200,000 k-and q-points were sampled to evaluate Eq. (5). With this dense sampling, the calculated electron (hole) mobility at 350 K was 912.9 (396.4) cm 2 /Vs, which reproduces previously reported values well [23,24].…”

Section: Dft Calculationssupporting

confidence: 85%

“…The calculated energy relaxation rate in the high-temperature case is in agreement with a previously reported result. Based on a Monte Carlo simulation using empirical pseudopotentials, the energy loss rate per electron carrier was estimated as ~0.4 eV/ps at 𝐸 = 30 kV/cm [5]. Converting our energy relaxation rate per unit cell to that per electron carrier yields a value of 0.352 eV/ps at 𝐸 = 32 kV/cm.…”

Section: B Microscopic Detail Of Energy Relaxation Ratementioning

confidence: 99%

“…Recently, by conducting a full-band Monte Carlo simulation, Pop et al [4] found that electron energy is mostly transferred to phonons with a low group velocity. Fischetti et al [5] revealed that acoustic phonons significantly contribute to the energy relaxation process. This contradicts the commonly accepted mechanism that most of the energy relaxation is caused by optical phonons.…”

Section: Introductionmentioning

confidence: 99%

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Ab initio analysis for the initial process of Joule heating in semiconductors

Minamitani

2021

Phys. Rev. B

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To investigate the initial process of Joule heating in semiconductors microscopically and quantitatively, we developed a theoretical framework for the ab initio evaluation of the carrier energy relaxation in semiconductors under a high electric field using a combination of the two-temperature model and the Boltzmann equation. We employed the method for bulk silicon as a typical example.Consequently, we found a remarkable difference in the energy relaxation processes of the electron and hole carriers. The longitudinal acoustic and optical phonons at the zone boundary contribute to the energy relaxation of electron carriers, whereas they contribute negligibly to that of the hole carriers.In addition, at the band edge, the energy relaxation rate is maximized for the electron carriers, whereas it is suppressed for the hole carriers. These differences stem from the presence/absence of intervalley scattering processes and isotropic/anisotropic band structures in electrons and holes. Our results lay the foundation for controlling the thermal generation in semiconductors by material design.Recent progress in ab initio calculations by combining density functional theory (DFT) and the Wannier interpolation technique [17][18][19][20] has enabled the evaluation of electron-phonon coupling with '("" , (1)where 𝑛 𝐪 represents the distribution function of the phonons,

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Section: Dft Calculationssupporting

confidence: 85%

Section: B Microscopic Detail Of Energy Relaxation Ratementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ab initio analysis for the initial process of Joule heating in semiconductors

Minamitani

2021

Phys. Rev. B

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“…8. Finally, these ab initio calculations [55,140] revealed that acoustic-phonon scattering in silicon is much more important than previously thought [141].…”

Section: 11mentioning

confidence: 98%

First-principles calculations of charge carrier mobility and conductivity in bulk semiconductors and two-dimensional materials

et al. 2020

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One of the fundamental properties of semiconductors is their ability to support highly tunable electric currents in the presence of electric fields or carrier concentration gradients. These properties are described by transport coefficients such as electron and hole mobilities. Over the last decades, our understanding of carrier mobilities has largely been shaped by experimental investigations and empirical models. Recently, advances in electronic structure methods for real materials have made it possible to study these properties with predictive accuracy and without resorting to empirical parameters. These new developments are unlocking exciting new opportunities, from exploring carrier transport in quantum matter to in silico designing new semiconductors with tailored transport properties. In this article, we review the most recent developments in the area of ab initio calculations of carrier mobilities of semiconductors. Our aim is threefold: to make this rapidly-growing research area accessible to a broad community of condensed-matter theorists and materials scientists; to identify key challenges that need to be addressed in order to increase the predictive power of these methods; and to identify new opportunities for increasing the impact of these computational methods on the science and technology of advanced materials. The review is organized in three parts. In the first part, we offer a brief historical overview of approaches to the calculation of carrier mobilities, and we establish the conceptual framework underlying modern ab initio approaches. We summarize the Boltzmann theory of carrier transport and we discuss its scope of applicability, merits, and limitations in the broader context of many-body Green's function approaches. We discuss recent implementations of the Boltzmann formalism within the context of density functional theory and many-body perturbation theory calculations, placing an emphasis on the key computational challenges and suggested solutions. In the second part of the article, we review applications of these methods to materials of current interest, from three-dimensional semiconductors to layered and two-dimensional materials.In particular, we discuss in detail recent investigations of classic materials such as silicon, diamond, gallium arsenide, gallium nitride, gallium oxide, and lead halide perovskites as well as lowdimensional semiconductors such as graphene, silicene, phosphorene, molybdenum disulfide, and indium selenide. We also review recent efforts toward highthroughput calculations of carrier transport. In the last part, we identify important classes of materials for which an ab initio study of carrier mobilities arXiv:1908.01733v1 [cond-mat.mtrl-sci] 5 Aug 2019First-principles calculations of charge carrier mobility and conductivity in bulk semiconductors and two-dimensional mate is warranted. We discuss the extension of the methodology to study topological quantum matter and materials for spintronics and we comment on the possibility of incorporating Berry-phase effects ...

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“…Energy loss via acoustic phonon emission is neglected and only optical phonon emission is considered. However, a recent study [28] suggests acoustic phonon emission may be a dominant energy loss mechanism and may be considered in future versions of this model.…”

Section: Energy Value Of Shaken-off Electron (Ev)mentioning

confidence: 99%

Simulating 50 keV X-ray Photon Detection in Silicon with a Down-Conversion Layer

Anagnost

Lee

Wang

et al. 2021

Sensors

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Simulation results are presented that explore an innovative, new design for X-ray detection in the 20–50 keV range that is an alternative to traditional direct and indirect detection methods. Typical indirect detection using a scintillator must trade-off between absorption efficiency and spatial resolution. With a high-Z layer that down-converts incident photons on top of a silicon detector, this design has increased absorption efficiency without sacrificing spatial resolution. Simulation results elucidate the relationship between the thickness of each layer and the number of photoelectrons generated. Further, the physics behind the production of electron-hole pairs in the silicon layer is studied via a second model to shed more light on the detector’s functionality. Together, the two models provide a greater understanding of this detector and reveal the potential of this novel form of X-ray detection.

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“Hot electrons in Si lose energy mostly to optical phonons”: Truth or myth?

Cited by 19 publications

References 62 publications

Ab initio analysis for the initial process of Joule heating in semiconductors

Ab initio analysis for the initial process of Joule heating in semiconductors

First-principles calculations of charge carrier mobility and conductivity in bulk semiconductors and two-dimensional materials

Simulating 50 keV X-ray Photon Detection in Silicon with a Down-Conversion Layer

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