APL Materials (Dec 2014)

Direct observation of bi-alkali antimonide photocathodes growth via in operando x-ray diffraction studies

  • M. Ruiz-Osés,
  • S. Schubert,
  • K. Attenkofer,
  • I. Ben-Zvi,
  • X. Liang,
  • E. Muller,
  • H. Padmore,
  • T. Rao,
  • T. Vecchione,
  • J. Wong,
  • J. Xie,
  • J. Smedley

DOI
https://doi.org/10.1063/1.4902544
Journal volume & issue
Vol. 2, no. 12
pp. 121101 – 121101-5

Abstract

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Alkali antimonides have a long history as visible-light-sensitive photocathodes. This work focuses on the process of fabrication of the bi-alkali photocathodes, K2CsSb. In-situ synchrotron x-ray diffraction and photoresponse measurements were used to monitor phase evolution during sequential photocathode growth mode on Si(100) substrates. The amorphous-to-crystalline transition for the initial antimony layer was observed at a film thickness of 40 Å . The antimony crystalline structure dissolved upon potassium deposition, eventually recrystallizing upon further deposition into K-Sb crystalline modifications. This transition, as well as the conversion of potassium antimonide to K2CsSb upon cesium deposition, is correlated with changes in the quantum efficiency.