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Title: Electron-phonon relaxation and excited electron distribution in gallium nitride

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 low-energy 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” largely covers the conduction band. The shape of the high-energy “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 an irradiated GaN. Probabilities of optical excitations from the valence to conduction band and electron-phonon coupling probabilities in GaN were calculated by the density functional perturbation theory. Our calculation of both parts of distribution function in galliummore » nitride shows that when the speed of the 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 essentially affect the charge transport in the irradiated and highly doped semiconductors.« less

Authors:
 [1];  [2];  [3];  [4];  [4];  [3];  [4];  [5];  [3];  [5]
  1. Institute of Solid State Chemistry, Urals Branch of the Russian Academy of Sciences, Pervomayskaya st. 91, Yekaterinburg (Russian Federation)
  2. (DIPC), P. Manuel de Lardizabal 4, 20018 San Sebastian (Spain)
  3. Donostia International Physics Center (DIPC), P. Manuel de Lardizabal 4, 20018 San Sebastian (Spain)
  4. (Russian Federation)
  5. (Spain)
Publication Date:
OSTI Identifier:
22598850
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 120; Journal Issue: 8; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CHARGE TRANSPORT; COMPARATIVE EVALUATIONS; DENSITY FUNCTIONAL METHOD; DISTRIBUTION; DISTRIBUTION FUNCTIONS; DOPED MATERIALS; ELECTRON CAPTURE; ELECTRON-PHONON COUPLING; ELECTRONS; EXTERNAL IRRADIATION; GALLIUM NITRIDES; PERTURBATION THEORY; PHONONS; RECOMBINATION; RELAXATION; SCATTERING; SEMICONDUCTOR MATERIALS; TRAPPING; VELOCITY

Citation Formats

Zhukov, V. P., Donostia International Physics Center, Tyuterev, V. G., E-mail: valtyut00@mail.ru, Tomsk State Pedagogical University, Kievskaya st. 60, Tomsk, Tomsk State University, Lenin st. 36, Tomsk, Chulkov, E. V., Tomsk State University, Lenin st. 36, Tomsk, Departamento de Fisica de Materiales, Facultad de Ciencias Qumicas, UPV/EHU and Centro de Fisica de Materiales CFM-MPC and Centro Mixto CSIC-UPV/EHU, Apdo. 1072, 20080 San Sebastian, Echenique, P. M., and Departamento de Fisica de Materiales, Facultad de Ciencias Qumicas, UPV/EHU and Centro de Fisica de Materiales CFM-MPC and Centro Mixto CSIC-UPV/EHU, Apdo. 1072, 20080 San Sebastian. Electron-phonon relaxation and excited electron distribution in gallium nitride. United States: N. p., 2016. Web. doi:10.1063/1.4961874.
Zhukov, V. P., Donostia International Physics Center, Tyuterev, V. G., E-mail: valtyut00@mail.ru, Tomsk State Pedagogical University, Kievskaya st. 60, Tomsk, Tomsk State University, Lenin st. 36, Tomsk, Chulkov, E. V., Tomsk State University, Lenin st. 36, Tomsk, Departamento de Fisica de Materiales, Facultad de Ciencias Qumicas, UPV/EHU and Centro de Fisica de Materiales CFM-MPC and Centro Mixto CSIC-UPV/EHU, Apdo. 1072, 20080 San Sebastian, Echenique, P. M., & Departamento de Fisica de Materiales, Facultad de Ciencias Qumicas, UPV/EHU and Centro de Fisica de Materiales CFM-MPC and Centro Mixto CSIC-UPV/EHU, Apdo. 1072, 20080 San Sebastian. Electron-phonon relaxation and excited electron distribution in gallium nitride. United States. doi:10.1063/1.4961874.
Zhukov, V. P., Donostia International Physics Center, Tyuterev, V. G., E-mail: valtyut00@mail.ru, Tomsk State Pedagogical University, Kievskaya st. 60, Tomsk, Tomsk State University, Lenin st. 36, Tomsk, Chulkov, E. V., Tomsk State University, Lenin st. 36, Tomsk, Departamento de Fisica de Materiales, Facultad de Ciencias Qumicas, UPV/EHU and Centro de Fisica de Materiales CFM-MPC and Centro Mixto CSIC-UPV/EHU, Apdo. 1072, 20080 San Sebastian, Echenique, P. M., and Departamento de Fisica de Materiales, Facultad de Ciencias Qumicas, UPV/EHU and Centro de Fisica de Materiales CFM-MPC and Centro Mixto CSIC-UPV/EHU, Apdo. 1072, 20080 San Sebastian. 2016. "Electron-phonon relaxation and excited electron distribution in gallium nitride". United States. doi:10.1063/1.4961874.
@article{osti_22598850,
title = {Electron-phonon relaxation and excited electron distribution in gallium nitride},
author = {Zhukov, V. P. and Donostia International Physics Center and Tyuterev, V. G., E-mail: valtyut00@mail.ru and Tomsk State Pedagogical University, Kievskaya st. 60, Tomsk and Tomsk State University, Lenin st. 36, Tomsk and Chulkov, E. V. and Tomsk State University, Lenin st. 36, Tomsk and Departamento de Fisica de Materiales, Facultad de Ciencias Qumicas, UPV/EHU and Centro de Fisica de Materiales CFM-MPC and Centro Mixto CSIC-UPV/EHU, Apdo. 1072, 20080 San Sebastian and Echenique, P. M. and Departamento de Fisica de Materiales, Facultad de Ciencias Qumicas, UPV/EHU and Centro de Fisica de Materiales CFM-MPC and Centro Mixto CSIC-UPV/EHU, Apdo. 1072, 20080 San Sebastian},
abstractNote = {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 low-energy 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” largely covers the conduction band. The shape of the high-energy “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 an irradiated GaN. Probabilities of optical excitations from the valence to conduction band and electron-phonon 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 the 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 essentially affect the charge transport in the irradiated and highly doped semiconductors.},
doi = {10.1063/1.4961874},
journal = {Journal of Applied Physics},
number = 8,
volume = 120,
place = {United States},
year = 2016,
month = 8
}
  • We report on the direct measurement of the electron-phonon relaxation time, τ{sub eph}, in disordered TiN films. Measured values of τ{sub eph} are from 5.5 ns to 88 ns in the 4.2 to 1.7 K temperature range and consistent with a T{sup −3} temperature dependence. The electronic density of states at the Fermi level N{sub 0} is estimated from measured material parameters. The presented results confirm that thin TiN films are promising candidate-materials for ultrasensitive superconducting detectors.
  • We report the measured phonon density of states of a bulk GaN powder by time-of-flight neutron spectroscopy. The observed one-phonon excitation spectrum consists of two broad bands centered at about 23 and 39 meV corresponding to the acoustic and the first group of optical phonons; two sharp bands of upper optic modes at about 75 and 86 meV; and a gap of 45{endash}65 meV. The phonon dispersion curves, lattice specific heat, and Debye temperature are calculated from fitting the data with a rigid-ion model. {copyright} {ital 1998 American Institute of Physics.}
  • No abstract prepared.
  • We demonstrate the excitation of localized surface phonon polaritons in an array of sub-diffraction pucks fabricated in an epitaxial layer of gallium nitride (GaN) on a silicon carbide (SiC) substrate. The array is characterized via polarization- and angle-dependent reflection spectroscopy in the mid-infrared, and coupling to several localized modes is observed in the GaN Reststrahlen band (13.4–18.0 μm). The same structure is simulated using finite element methods and the charge density of the modes are studied; transverse dipole modes are identified for the transverse electric and magnetic polarizations and a quadrupole mode is identified for the transverse magnetic polarization. The measuredmore » mid-infrared spectrum agrees well with numerically simulated spectra. This work could enable optoelectronic structures and devices that support surface modes at mid- and far-infrared wavelengths.« less
  • Gallium nitride nanowires (GaN-NWs) of diameters ranging from 20 to 80 nm were grown on the p-type Si substrate by Thermal Chemical Vapor Deposition (TCVD) using Iron (Fe) catalyst via VLS mechanism. Raman and FTIR spectra reveal the presence of broad transverse optic (TO) and longitudinal optic (LO) phonon peak spreads over 500-600 cm{sup −1} and 720 cm{sup −1} respectively. The detail deconvolution of integrated transverse and longitudinal phonon analysis reveals phonon confinement brought out by incorporation of hydrogen atom. The red shifts of TO and LO phonon peak position indicates nanosized effect. I{sub A1(LO)}/I{sub A1(TO)} increases from 0.073 to 1.0 and theirmore » respective fwhm{sub A1(LO)}/fwhm{sub A1(TO)} also increases from 0.71 to 1.31 with increasing H{sub 2} flow rate. E{sub 1}(LO) - E{sub 1}(TO) and A{sub 1}(LO) - A{sub 1}(TO) increases from 173.83 to 190.73 and 184.89 to 193.22 respectively. Apart from this usual TO and LO phonon, we have found Surface Optic (SO) phonon at 671 cm{sup −1} in FTIR spectra. The intensity of PL peak increases with increasing H{sub 2} dilution reveals efficient passivation of defect centre at surface of GaN-NWs.« less