Energy Functional Materials Engineering Laboratory

On Jun. 6, Dr. Alexandros Emborasa (ETH Zurich) visited us and lectured on neuromorphic computing.

Lecturer: Dr. Alexandros Emborasa (ETH Zurich)
Seminar title: Neuromorphic Computing: From Devices to Applications

Our paper entitled “Novel Route for Enhancing Piezoelectricity of Ferroelectric Films: Controlling Nontrivial Polarization States in Pb(Zr, Ti)O₃ Monodomain Superlattice Structure” has been published in ACS Appl. Mater. Interfaces. We found that (111)-epitaxial artificial superlattice thin films consisting of Pb(Zr_0.4Ti_0.6)O₃ and Pb(Zr_0.6Ti_0.4)O₃ can be stabilized into unique monodomain state, which results in the piezoelectric response larger than the typical clamped films with the same chemical compositions.

Citation: ACS Appl. Mater. Interfaces 16, 16145 (2024).

Our paper entitled “Extraordinarily Large Contribution Ratio of Ferroelastic Domain Switching to Piezoresponse in Monoclinic (K, Na)NbO₃ Films” has been published in Adv. Electron. Mater. We found that the extrinsic contribution to the piezoresponse in (111)epitaxial monoclinic (K, Na)NbO₃ films is extraordinarily large, over 100% under moderate electric fields.

Citation: Adv. Electron. Mater. 10, 2300405 (2024).

Our paper entitled “Dynamic Electrical Response of Vortex Polarization in (Pb_0.9Sr_0.1)TiO₃/SrTiO₃ Artificial Superlattice Thin Films” has been published in Appl. Phys. Lett. We found that the reorientation of dipole moments in the vortex domains is susceptible to the applied electric field pulses of 500 μs and is a reversible process. Although the centrosymmetric vortex domain structure is not considered to exhibit piezoelectricity, an evident change in the out-of-plane lattice constant with the applied electric field was revealed.

Citation: APL 121, 172904 (2022).

Our paper entitled “Strong Electro-optic Effect in Mg Incorporated ZnO Thin Films” has been published in Appl. Phys. Lett. We found that the Mg incorporation enhances the linear EO response significantly. In particular, the Zn_0.72Mg_0.28O thin film showed an effective EO coefficient of 7.6 pm/V, which is over three times larger than the reported values for ZnO-based thin films and over twice larger than that of ZnO single crystals. This study is the collaborative research with Dr. Meng of Institute of Semiconductors, Chinese Academy of Sciences.

Citation: APL 121, 152903 (2022).

Our paper entitled “Effect of Ni Doping on the Electro-optic Property in K(Ta_0.6Nb_0.4)O₃ Films” has been published in Jpn. J. Appl. Phys. We found that a larger withstand electric field was achieved by Ni doping, therefore, the variation of refractive index by the applicable maximum electric field was increased.

Citation: JJAP 61, SN1005 (2022).

Our paper entitled “Optimizing the Growth of K(Ta_0.6Nb_0.4)O₃ Films using Pulsed Laser Deposition and their Electro-optic Property” has been published in J. Ceram. Soc. Jpn. We revealed that the optimized KTN film showed the maximum EO coefficient r_c of 42 pm/V, which is larger than the previously reported value for KTN thin films having the same composition.

Citation: JCSJ 130, 424 (2022).

Our paper entitled “Revealing Intrinsic Electro-optic Effect in Single Domain Pb(Zr, Ti)O₃ Thin Films” has been published in Appl. Phys. Lett. We revealed the intrinsic EO effect in PZT using the single domain films grown on CaF₂ substrates. Our finding shows that the intrinsic EO effect is enhanced in PZT, which is similar to the enhancement seen in the dielectric and piezoelectric constants. Moreover, it tells us that most of the reported EO response in PZT films is supported by additional extrinsic contributions.

Citation: APL 119, 102902 (2021).

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Our paper entitled “Influence of Orientation on the Electro-optic Effect in Epitaxial Y-doped HfO₂ Ferroelectric Thin Films” has been published in Jpn. J. Appl. Phys. We found that the (111)-Y-HfO₂ film showed a larger EO response than that of the (100)-Y-HfO₂ film, which is reasonable considering the difference in remnant polarization between the (100)- and (111)-Y-HfO₂ films.

Citation: JJAP 60, SFFB13 (2021).

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Our paper entitled “Linear Electro-optic Effect in Ferroelectric HfO₂-based Epitaxial Thin Films” has been published in Jpn. J. Appl. Phys. Rapid Communication. We found that the Y-HfO₂ film showed a linear EO response, owing to its ferroelectricity. The observed results indicate that ferroelectric HfO₂-based films are viable candidates for CMOS-compatible EO devices.

Citation: JJAP 60, 070905 (2021).

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