Insights into Antiferroelectric Materials from Photoelectron Spectroscopy
Prof. Dr. Andreas Klein Electronic Structure of Materials Institute of Materials Science Technical University of Darmstadt
Binxiang Huang, Nicole Bein, Andreas Klein
X-ray photoelectron spectroscopy measurements on Pb-containing and Pb-free antiferroelectric materials will be presented. Analysis of the Fermi energy in conjunction with electrical properties of NaNbO3 provide insights into the nature of the electronic states and the energy gap of NaNbO3, which is suggested to be significantly larger than the optically measured gap. For Pb(Zr,Sn,Ti)O3, the measurements revealed that the dependence of Schottky barrier height on polarization is only observed for compositions revealing ferroelectric hysteresis loops, while the effect is absent if double hysteresis loops are observed. Moreover, we have studied the electrical degradation at elevated temperature inside the XPS system. An electrochemical reduction of Pb is observed, which indicates that electron trapping on Pb is limiting the electrical conductivity of donor-doped, Zr-rich Pb(Zr,Sn,Ti)O3.
About the FLAME-inars
The FLAME-inars are organized by the collaborative project FLAME at TU Darmstadt, in which electronic-structure-property relationships are being developed and exploited to realize novel lead-free antiferroelectric compounds. The seminars will gather experts in processing, characterization and theory to discuss materials and applications, bulk and thin films, fundamental properties, electronic structure & defects, and related aspects.