Realizing perovskite interfaces for high-mobility two-dimensional electron gases

O. Bierwagen (PDI), J. Schwarzkopf (IKZ), M. Bickermann (IKZ), K. Char (Seoul National University), M. Albrecht (IKZ)

Cluster G; Funded by the Leibniz association under Grant No. K74/2017

Realizing two-dimensional electron gases (2DEG) with high room-temperature (electron) mobility using perovskite oxides is the holy grail for multifunctional electronic devices. The interface between the lattice-matched perovskites LaInO3 and BaSnO3 is ideally suited for this purpose.

A team of bulk crystal growers, epitaxy, and electron microscopy experts from GraFOx cluster G laid the foundation to realize this interface with highest structural quality.

They developed the growth of bulk BaSnO3 [1] and LaInO3 [2] substrates for dislocation-free epitaxial growth of the heterostructure, demonstrated epitaxy of the individual layers [3, 4], and realized the heterostructure by pulsed laser deposition [5] and molecular beam epitaxy [Figures].

The 2DEG is induced by the combination of the polar and non-polar perovskites LaInO3 and BaSnO3. Epitaxial combination with further perovskites (chemical formula ABO3) allows to harness their physical properties (governed by the choice of cations A and B) to enhance the functionality of the 2DEG.

While the 2DEG itself can be applied in transparent field effect transistors (FETs), combination with a ferroelectric is projected to allow realization of a ferroelectric FET as a building block for energy-efficient in-memory computing or non-volatile memory.

[1]

Galazka, Z., Uecker, R., Irmscher, K., Klimm, D., Bertram, R., Kwasniewski, A., Naumann, M., Schewski, R., Pietsch, M., Juda, U., Fiedler, A., Albrecht, M., Ganschow, S., Markurt, T., Guguschev, C., & Bickermann, M. (2017). Melt growth and properties of bulk BaSnO₃ single crystals. Journal of Physics: Condensed Matter, 29(7), 075701. https://doi.org/10.1088/1361-648X/aa50e2
[2]
Galazka, Z., Irmscher, K., Ganschow, S., Zupancic, M., Aggoune, W., Draxl, C., Albrecht, M., Klimm, D., Kwasniewski, A., Schulz, T., Pietsch, M., Dittmar, A., Grueneberg, R., Juda, U., Schewski, R., Bergmann, S., Cho, H., Char, K., Schroeder, T., & Bickermann, M. (2021). Melt growth and physical properties of bulk LaInO₃ single crystals. Physica Status Solidi (a), 218(16), 2100016. https://doi.org/10.1002/pssa.202100016
[3]
Pfützenreuter, D., Zupancic, M., Galazka, Z., Schewski, R., Dittmar, A., Irmscher, K., Albrecht, M., & Schwarzkopf, J. (2021). Epitaxial BaSnO₃ thin films with low dislocation density grown on lattice matched LaInO₃ substrates. Nanotechnology, 32(50), 505609. https://doi.org/10.1088/1361-6528/ac291c
[4]
Hoffmann, G., Zupancic, M., Klimm, D., Schewski, R., Albrecht, M., Ramsteiner, M., Zohair, F., & Bierwagen, O. (2023). Adsorption-controlled plasma-assisted molecular beam epitaxy of LaInO3 on DyScO3 (110): Growth window, strain relaxation, and domain pattern. Physical Review Materials, 7(8), 084605. https://doi.org/10.1103/PhysRevMaterials.7.084605
[5]
Pfützenreuter, D., Kim, S., Cho, H., Bierwagen, O., Zupancic, M., Albrecht, M., Char, K., & Schwarzkopf, J. (2022). Confinement of electrons at the LaInO₃/BaSnO₃ heterointerface. Advanced Materials Interfaces, 9, 2201279. https://doi.org/10.1002/admi.202201279