Energy band alignment of antiferroelectric (Pb,La)(Zr,Sn,Ti)O3

The energy band alignment of antiferroelectric (Pb,La)(Zr,Sn,Ti)O-3 is studied with photoelectron spectroscopy using interfaces with high work function RuO2 and low work function Sn-doped In2O3 (ITO). It is demonstrated how spectral deconvolution can be used to determine absolute Schottky barrier heights for insulating materials with a high accuracy. Using this approach it is found that the valence band maximum energy of (Pb,La)(Zr,Sn,Ti)O-3 is found to be comparable to that of Pb- and Bi-containing ferroelectric materials, which is similar to 1 eV higher than that of BaTiO3. The results provide additional evidence for the occupation of the 6s orbitals as origin of the higher valence band maximum, which is directly related to the electrical properties of such compounds. The results also verify that the energy band alignment determined by photoelectron spectroscopy of as-deposited electrodes is not influenced by polarisation, The electronic structure of (Pb,La)(Zr,Sn,Ti)O-3 should enable doping of the material without strongly modifying its insulating properties, which is crucial for high energy density capacitors. Moreover, the position of the energy bands should result in a great freedom of selecting electrode materials in terms of avoiding charge injection. (C) 2017 Elsevier B.V. All rights reserved.