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Søren Ulstrup

How Indium Nitride Senses Water

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  • Vedran Jovic, University of Auckland, Lawrence Berkeley National Laboratory
  • ,
  • Simon Moser, Lawrence Berkeley National Laboratory
  • ,
  • Søren Ulstrup
  • Dana Goodacre, University of Auckland
  • ,
  • Emmanouil Dimakis, Boston University
  • ,
  • Roland Koch, Lawrence Berkeley National Laboratory
  • ,
  • Georgios Katsoukis, Lawrence Berkeley National Laboratory
  • ,
  • Luca Moreschini, Lawrence Berkeley National Laboratory
  • ,
  • Sung Kwan Mo, Lawrence Berkeley National Laboratory
  • ,
  • Chris Jozwiak, Lawrence Berkeley National Laboratory
  • ,
  • Aaron Bostwick, Lawrence Berkeley National Laboratory
  • ,
  • Eli Rotenberg, Lawrence Berkeley National Laboratory
  • ,
  • Theodore D. Moustakas, Boston University
  • ,
  • Kevin E. Smith, University of Auckland, Boston University

The unique electronic band structure of indium nitride InN, part of the industrially significant III-N class of semiconductors, offers charge transport properties with great application potential due to its robust n-type conductivity. Here, we explore the water sensing mechanism of InN thin films. Using angle-resolved photoemission spectroscopy, core level spectroscopy, and theory, we derive the charge carrier density and electrical potential of a two-dimensional electron gas, 2DEG, at the InN surface and monitor its electronic properties upon in situ modulation of adsorbed water. An electric dipole layer formed by water molecules raises the surface potential and accumulates charge in the 2DEG, enhancing surface conductivity. Our intuitive model provides a novel route toward understanding the water sensing mechanism in InN and, more generally, for understanding sensing material systems beyond InN.

Original languageEnglish
JournalNano Letters
Volume17
Issue12
Pages (from-to)7339-7344
Number of pages6
ISSN1530-6984
DOIs
Publication statusPublished - 13 Dec 2017
Externally publishedYes

    Research areas

  • ARPES, quantum well, Sensor, surface electronic potential, two-dimensional electron gas (2DEG)

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