Maximal Visible Light Energy Transfer to Ultrathin Semiconductor Films Enabled by Dispersion Control

Gwang Hun Jung, Seok Jae Yoo, Jin Soo Kim, Q. Han Park

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


Increasing light absorption in an ultrathin semiconductor is critical for developing thin-film photovoltaic devices. Here, it is shown that a maximal absorption of visible light is possible through controlling the dispersion of thin-film materials. The ideal dispersion relation is determined for the permittivity of a thin film placed on a reflector with a dielectric spacer, and it is explained how the ideal dispersion relation can be realized for semiconductor materials possessing bandgaps. To experimentally verify dispersion control and maximal absorption, the permittivity of lead selenide (PbSe) thin film is tailored by controlling its polycrystallinity through the sputtering conditions. The measured reflectance of a dispersion-controlled PbSe film (9 nm) deposited on an SiO 2 (48 nm)/Al substrate shows a record level of absorbance for PbSe film of 88% taken as an average over the entire visible spectrum. This value is close to the theoretical maximum value of 95%. Overall, the dispersion control scheme offers promising avenues for thin-film solar cell research.

Original languageEnglish
Article number1801229
JournalAdvanced Optical Materials
Issue number7
Publication statusPublished - 2019 Apr 4

Bibliographical note

Publisher Copyright:
© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim


  • light absorption, permittivity tailoring
  • ultrathin semiconductor films

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics


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