Effects of surface condition on the work function and valence-band position of ZnSnN2

Amanda M. Shing, Yulia Tolstova, Nathan S Lewis, Harry A. Atwater

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

ZnSnN2 is an emerging wide band gap earth-abundant semiconductor with potential applications in photonic devices such as solar cells, LEDs, and optical sensors. We report the characterization by ultraviolet photoelectron spectroscopy and X-ray photoelectron spectroscopy of reactively radio-frequency sputtered II–IV-nitride ZnSnN2 thin films. For samples transferred in high vacuum, the ZnSnN2 surface work function was 4.0 ± 0.1 eV below the vacuum level, with a valence-band onset of 1.2 ± 0.1 eV below the Fermi level. The resulting band diagram indicates that the degenerate bulk Fermi level position in ZnSnN2 shifts to mid-gap at the surface due to band bending that results from equilibration with delocalized surface states within the gap. Brief (< 10 s) exposures to air, a nitrogen-plasma treatment, or argon-ion sputtering caused significant chemical changes at the surface, both in surface composition and interfacial energetics. The relative band positioning of the n-type semiconductor against standard redox potentials indicated that ZnSnN2 has an appropriate energy band alignment for use as a photoanode to effect the oxygen-evolution reaction.

Original languageEnglish
Article number735
JournalApplied Physics A: Materials Science and Processing
Volume123
Issue number12
DOIs
Publication statusPublished - Dec 1 2017

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Valence bands
Fermi level
Vacuum
Ultraviolet photoelectron spectroscopy
Semiconductor materials
Nitrogen plasma
Photonic devices
Argon
Optical sensors
Surface states
Nitrides
Surface structure
Band structure
Light emitting diodes
Sputtering
Solar cells
Energy gap
X ray photoelectron spectroscopy
Earth (planet)
Ions

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)

Cite this

Effects of surface condition on the work function and valence-band position of ZnSnN2 . / Shing, Amanda M.; Tolstova, Yulia; Lewis, Nathan S; Atwater, Harry A.

In: Applied Physics A: Materials Science and Processing, Vol. 123, No. 12, 735, 01.12.2017.

Research output: Contribution to journalArticle

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