AIP Advances (Oct 2017)

Conditions for optimal efficiency of PCBM-based terahertz modulators

  • Hyung Keun Yoo,
  • Hanju Lee,
  • Kiejin Lee,
  • Chul Kang,
  • Chul-Sik Kee,
  • In-Wook Hwang,
  • Joong Wook Lee

DOI
https://doi.org/10.1063/1.5001561
Journal volume & issue
Vol. 7, no. 10
pp. 105008 – 105008-6

Abstract

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We demonstrate the conditions for optimal modulation efficiency of active terahertz modulators based on phenyl-C61-butyric acid methyl ester (PCBM)-silicon hybrid structures. Highly efficient active control of the terahertz wave modulation was realized by controlling organic film thickness, annealing temperature, and laser excitation wavelength. Under the optimal conditions, the modulation efficiency reached nearly 100%. Charge distributions measured with a near-field scanning microwave microscanning technique corroborated the fact that the increase of photo-excited carriers due to the PCBM–silicon hybrid structure enables the enhancement of active modulation efficiency.