Quantum behavior of terahertz photoconductivity in silicon nanocrystals networks

V. Pushkarev, T. Ostatnický, H. Němec, T. Chlouba, F. Trojánek, P. Malý, M. Zacharias, S. Gutsch, D. Hiller, and P. Kužel
Phys. Rev. B 95, 125424 – Published 17 March 2017

Abstract

Quantum-size effects are essential for understanding the terahertz conductivity of semiconductor nanocrystals, particularly at low temperatures. We derived a quantum mechanical expression for the linear terahertz response of nanocrystals; its introduction into an appropriate effective medium model provides a comprehensive microscopic approach for the analysis of terahertz conductivity spectra as a function of frequency, temperature, and excitation fluence. We performed optical pump–terahertz probe experiments in multilayer Si quantum dot networks with various degrees of percolation at 300 and 20 K and with variable pump fluence (initial carrier density) over nearly three orders of magnitude. Our theoretical approach was successfully applied to quantitatively interpret all the measured data within a single model. A careful data analysis made it possible to assess the distribution of sizes of nanocrystals participating to the photoconduction. We show and justify that such conductivity-weighted distribution may differ from the size distribution obtained by standard analysis of transmission electron microscopy images.

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  • Received 27 January 2017
  • Revised 22 February 2017

DOI:https://doi.org/10.1103/PhysRevB.95.125424

©2017 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

V. Pushkarev1, T. Ostatnický2, H. Němec1, T. Chlouba2, F. Trojánek2, P. Malý2, M. Zacharias3, S. Gutsch3, D. Hiller3, and P. Kužel1,*

  • 1Institute of Physics ASCR, Na Slovance 2, 18221 Prague 8, Czech Republic
  • 2Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 3, 12116 Prague 2, Czech Republic
  • 3IMTEK Faculty of Engineering, Albert-Ludwigs-University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg, Germany

  • *kuzelp@fzu.cz

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Issue

Vol. 95, Iss. 12 — 15 March 2017

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