• Relaxation of femtosecond photoexcited electrons in a polar indirect band-gap semiconductor nanoparticle

    • Fulltext

       

        Click here to view fulltext PDF


      Permanent link:
      https://www.ias.ac.in/article/fulltext/pram/064/01/0111-0118

    • Keywords

       

      Electron gas; Fermi gas; semiconductor compounds

    • Abstract

       

      A model calculation is given for the energy relaxation of a non-equilibrium distribution of hot electrons (holes) prepared in the conduction (valence) band of a polar indirect band-gap semiconductor, which has been subjected to homogeneous photoexcitation by a femtosecond laser pulse. The model assumes that the pulsed photoexcitation creates two distinct but spatially interpenetrating electron and hole non-equilibrium subsystems that initially relax non-radiatively through the electron (hole)-phonon processes towards the conduction (valence) band minimum (maximum), and finally radiatively through the phonon-assisted electron-hole recombination across the band-gap, which is a relatively slow process. This leads to an accumulation of electrons (holes) at the conduction (valence) band minimum (maximum). The resulting peaking of the carrier density and the entire evolution of the hot electron (hole) distribution has been calculated. The latter may be time resolved by a pump-probe study. The model is particularly applicable to a divided (nanometric) polar indirect band-gap semiconductor with a low carrier concentration and strong electron-phonon coupling, where the usual two-temperature model [1-4] may not be appropriate.

    • Author Affiliations

       

      Navinder Singh1

      1. Optics Group, Raman Research Institute, Bangalore - 560 080, India
    • Dates

       
  • Pramana – Journal of Physics | News

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

© 2017-2019 Indian Academy of Sciences, Bengaluru.