Midinfrared Electro-optic Modulation in Few-Layer Black Phosphorus

Ruoming Peng, Kaveh Khaliji, Nathan Youngblood, Roberto Grassi, Tony Low, Mo Li

Research output: Contribution to journalArticlepeer-review

103 Scopus citations


Black phosphorus stands out from the family of two-dimensional materials as a semiconductor with a direct, layer-dependent bandgap spanning the visible to mid-infrared (mid-IR) spectral range. It is, therefore, a very promising material for various optoelectronic applications, particularly in the important mid-IR range. While mid-IR technology has been advancing rapidly, both photodetection and electro-optic modulation in the mid-IR rely on narrow-band compound semiconductors, which are difficult and expensive to integrate with the ubiquitous silicon photonics. For mid-IR photodetection, black phosphorus has already been proven to be a viable alternative. Here, we demonstrate electro-optic modulation of mid-IR absorption in few-layer black phosphorus. Our experimental and theoretical results find that, within the doping range obtainable in our samples, the quantum confined Franz-Keldysh effect is the dominant mechanism of electro-optic modulation. A spectroscopic study on samples with varying thicknesses reveals strong layer dependence in the interband transition between specific pairs of sub-bands. Our results show that black phosphorus is a very promising material to realizing efficient mid-IR modulators.

Original languageEnglish (US)
Pages (from-to)6315-6320
Number of pages6
JournalNano letters
Issue number10
StatePublished - Oct 11 2017

Bibliographical note

Publisher Copyright:
© 2017 American Chemical Society.


  • Black phosphorus
  • electro-absorptive modulation
  • electro-optic modulation
  • midinfrared
  • quantum confined Franz-Keldysh effect
  • transmission extinction measurement

MRSEC Support

  • Partial

PubMed: MeSH publication types

  • Journal Article
  • Research Support, U.S. Gov't, Non-P.H.S.


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