Energy band alignment between Pb(Zr,Ti)O3 and high and low work function conducting oxides-from hole to electron injection

The interface formation between Pb(Zr,Ti)O-3 (PZT) and RuO2 and between PZT and In2O3 : Sn (ITO), respectively, was characterized using in situ x-ray photoelectron spectroscopy (XPS). No interface reaction was observed for the interfaces studied. The Fermi level position at the interface (Schottky barrier height) is strongly different for the two electrode materials. A Fermi level position of 1.0 +/- 0.1 eV above the valence band maximum (VBM) is observed for the contact between PZT and the high work function oxide RuO2. For the contact between PZT and the low work function oxide ITO a Fermi level position of 2.1 +/- 0.2 eV above the VBM is found.