Ultralarge piezo- and pyroelectric responses in He implanted Gd:CeO2 films

• Applicant: Dr. Andreas Herklotz
• Subject Area: Experimental Condensed Matter Physics
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 575712790

Large electromechanical coupling phenomena have recently been discovered in rare-earth doped CeO2 thin films. In our preliminary work we demonstrate that giant electromechanical responses can be induced in epitaxial Gd-doped ceria thin films through He-ion implantation. The figures of merit for potential devices, such as pyroelectric and piezoelectric coefficients, have already reached those of state-of-the-art lead-containing ferroelectric materials in the low-frequency regime. These recent findings make rare-earth doped ceria films extremely promising to be harnessed in future thin film sensors and actuators. First, ceria is non-toxic and can thus be more widely applied than lead-containing devices. Second, post-synthesis ion implantation is a well-established technique in device fabrication and compatible with existing semiconductor processing infrastructure. Third, operating far from thermal equilibrium during ion implantation allows access to phase space that is not available through thermodynamic processes during standard thin film growth. Currently, a profound understanding of the mechanisms that drive the giant electromechanical effects is still lacking. Within this project we aim to employ various experimental strategies to explore these mechanisms in He-ion implanted rare-earth doped ceria films. Understanding and optimizing key implantation parameters will likely enhance figures of merit even further.

• DFG Programme: Research Grants
• International Connection: Denmark, USA
• Cooperation Partners: Professor Dr. David P. Cann; Dr. Daesung Park; Dr. Thomas Zac Ward