화학공학소재연구정보센터
Applied Surface Science, Vol.352, 73-81, 2015
Photoelectron spectroscopy and spectro-microscopy of Pb(Zr,Ti)O-3 (111) thin layers: Imaging ferroelectric domains with binding energy contrast
The ability of photoelectron spectro-microscopy with sub-micrometer lateral resolution to identify ferroelectric domains by analysis of surface band bendings is demonstrated on lead zirco-titanate PZT(1 1 1) thin films grown by pulsed laser deposition. Conventional synchrotron radiation X-ray photoelectron spectroscopy allowed one to derive the surface composition of the sample and evidenced shifts toward higher binding energy when the sample is subject to intense soft X-ray beam. A basic model is developed which supposes that photogenerated carriers reduce the depolarization field, yielding a lower torque applied to the ferroelectric polarization. As a consequence, the out-of-plane component of the polarization increases. Domain migration during irradiation with soft X-ray is inferred from the relative amplitude of the components with different binding energy. When the flux density of soft X-ray is on the order of 1011 photons/(s mu m(2)), metal Pb clusters are formed at the surface on areas with the out-of-plane component of the polarization pointing outwards only. (C) 2015 Elsevier B.V. All rights reserved.