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Title: Extended two-temperature model for ultrafast thermal response of band gap materials upon impulsive optical excitation

Thermal modeling and numerical simulations have been performed to describe the ultrafast thermal response of band gap materials upon optical excitation. A model was established by extending the conventional two-temperature model that is adequate for metals, but not for semiconductors. It considers the time- and space-dependent density of electrons photoexcited to the conduction band and accordingly allows a more accurate description of the transient thermal equilibration between the hot electrons and lattice. Ultrafast thermal behaviors of bismuth, as a model system, were demonstrated using the extended two-temperature model with a view to elucidating the thermal effects of excitation laser pulse fluence, electron diffusivity, electron-hole recombination kinetics, and electron-phonon interactions, focusing on high-density excitation.
Authors:
 [1] ;  [2] ; ; ;  [1] ;  [1] ;  [3]
  1. Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307 (United States)
  2. (Korea, Republic of)
  3. (Greece)
Publication Date:
OSTI Identifier:
22493261
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 143; Journal Issue: 19; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; BISMUTH; COMPUTERIZED SIMULATION; DENSITY; ELECTRON-PHONON COUPLING; ELECTRONS; ENERGY GAP; EXCITATION; HOLES; LASER RADIATION; RECOMBINATION; SEMICONDUCTOR MATERIALS; SPACE DEPENDENCE; TEMPERATURE DEPENDENCE; TRANSIENTS