films on graphene-covered crystalline substrates*

The use of substrates coated with an ultrathin two-dimensional (2D) material may bring several advantages when it comes to growing freestanding membranes. These advantages include substrate reusability, simplified film exfoliation, and the potential for reducing dislocation density in the epitaxial layer. However, the exact growth mechanism of perovskite oxides on crystalline substrates covered with a 2D material, such as monolayer or bilayer graphene, remains uncertain. This uncertainty stems from the fact that three possible growth mechanisms—specifically, remote epitaxy, pinhole-assisted epitaxy, and van der Waals epitaxy—can result in similar outcomes of epitaxial growth and film exfoliation [1]. In this talk, we will shed light on these mechanisms by examining the heteroepitaxial growth of SrTiO₃ films on various lattice-mismatched substrates covered with varying thicknesses of graphene.

[1] H. Yoon, T. K. Truttmann, F. Liu, B. E. Matthews, S. Choo, Q. Su, V. Saraswat, S. Manzo, M. S. Arnold, M. E. Bowden, J. K. Kawasaki, S. J. Koester, S. R. Spurgeon, S. A. Chambers and B. Jalan, "Free-Standing Epitaxial SrTiO₃ Nanomembranes via Remote Epitaxy using Hybrid Molecular Beam Epitaxy" Sci. Adv. 8, eadd5328 (2022)