Mid-wave to near-IR optoelectronic properties and epsilon-near-zero behavior in indium-doped cadmium oxide

Angela Cleri, John Tomko, Kathleen Quiambao-Tomko, Mario V. Imperatore, Yanglin Zhu, J. Ryan Nolen, Joshua Nordlander, Joshua D. Caldwell, Zhiqiang Mao, Noel C. Giebink, Kyle P. Kelley, Evan L. Runnerstrom, Patrick E. Hopkins, Jon Paul Maria

Research output: Contribution to journalArticlepeer-review

Abstract

Indium-doped cadmium oxide (In:CdO) thin films exhibit tunable epsilon-near-zero (ENZ) modal frequencies across a wide spectral range, bridging the mid-wave and near-infrared (IR). In:CdO thin films are prepared by reactive cosputtering from metallic Cd and In targets using high-power impulse magnetron sputtering (HiPIMS) and radio frequency sputtering, respectively. Using this approach, CdO thin films with carrier concentrations ranging from 2.3×1019 to 4.0×1020cm-3 and mobilities ranging from 300 to 400cm2/Vs are readily achieved. UV-VIS absorption spectra are used to measure optical bandgap, revealing a Burstein-Moss shift of 0.58 eV across the doping range investigated. Optical measurements demonstrate the tunability of near-perfect plasmonic ENZ absorption across the mid-wave and into the near-IR spectral ranges by controlling the carrier concentration through doping, while tuning the film thickness for impedance matching. In comparison to other dopants that can be introduced to HiPIMS-deposited CdO, In offers the largest range of carrier concentrations while maintaining high mobility, thus allowing for the widest accessibility of the IR spectrum of a single plasmonic material grown by sputtering.

Original languageEnglish (US)
Article number035202
JournalPhysical Review Materials
Volume5
Issue number3
DOIs
StatePublished - Mar 2021

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Physics and Astronomy (miscellaneous)

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