A study on XAFS analysis of Cs/GaAs NEA surface

Although NEA (negative electron affinity) surface has been attracting great interest, atomic level structure of the NEA surface has not been elucidated. In this work, Cs/GaAs NEA surfaces were analyzed by fluorescence XAFS (x-ray adsorption fine structure) method. Cs-LIII XAFS measurement was conducted on the Cs/GaAs surfaces obtained by Yo-Yo method. By analyzing the local structure around Cs from the XAFS spectra, it was shown that Cs-O-As (or Ga) or O-Cs-As (or Ga) structure might be formed on Cs/GaAs surface. The results suggested that single atomic layer of Cs was adsorbed on GaAs surface intermediated by O on the Cs/GaAs NEA surface.