Probing free carrier plasmons in doped semiconductors using spatially resolved electron energy loss spectroscopy

Hongbin Yang, Eric L. Garfunkel, Philip E. Batson

Research output: Contribution to journalArticlepeer-review

Abstract

We report spatially resolved measurements of free carrier collective excitations in a doped semiconductor. Using ∼10 meV resolution electron energy loss spectroscopy (EELS) in an electron microscope with Å spatial resolution, we identify both surface and bulk carrier plasmons at infrared energies in a freestanding film of indium tin oxide (ITO). The interference patterns of long wavelength propagating surface carrier plasmons are revealed using spatially resolved EELS, from which we extract a dispersion relation. We further show that the energies of these plasmons vary near the surfaces and grain boundaries of the film due to band bending. Modeling based on dielectric theory agrees very well with experimental results. Finally, carrier plasmons in amorphous and crystalline ITO films are compared. These results should also be helpful for understanding the free carrier plasmons in other doped semiconductors in nanoscale volumes.

Original languageEnglish
Article number205427
JournalPhysical Review B
Volume102
Issue number20
DOIs
Publication statusPublished - Nov 30 2020

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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