Heteroepitaxial Metal Halide Perovskites via Pulsed Laser Deposition

Epitaxial and heteroepitaxial growth of metal halide perovskites (MHP) offers a unique platform for better understanding of the correlation between materials’ properties and processing, as well as enable studies of polymorph stabilization and substrate-induced strain control.
Pulsed laser deposition (PLD), a physical vapor deposition technique, is a dry, single-source vapor-phase technique with unique properties to deposit metal halide perovskites on various substrates [1-5]. Here we discuss the use of PLD for the epitaxial growth of CH₃NH₃PbI₃ on KCl single crystal substrates and verified the stabilization of the cubic polymorph of CH₃NH₃PbI₃ with techniques such as reciprocal space maps, polar figures and EBSD [5]. Photoluminescence measurements confirm that the films have a bandgap of 1.64 to 1.66 eV corresponding to the cubic phase. Beyond CH₃NH₃PbI₃, we will discuss the cases of heteroepitaxy of CsSnI₃ and CsPbI₃, both having also a close lattice match with KCl substrates. The critical role of the PLD growth parameters to achieve epitaxy of either the hybrid or inorganic perovskites will be described.
Finally, and moving beyond 3D perovskites, the growth of highly oriented structures of (PEA)₂PbI₄ with PLD atop MHPs heteroepitaxial layers is demonstrated. X-ray diffraction, grazing incidence wide angle scattering, time-resolved PL and conductivity measurements and atomic force microscopy are furthermore employed to gain understanding of the structure, texture, morphology and carrier transport of the 2D/3D heteroepitaxial layers. This work demonstrates the benefits of vapor-based growth for 2D metal halide perovskites via PLD and paves the way for heterostructure and device integration.

References
[1] https://doi.org/10.1002/admi.202000162
[2] https://doi.org/10.1021/acs.chemmater.1c02054
[3] https://doi.org/10.1002/adfm.202300588
[4] https://doi.org/10.21203/rs.3.rs-3671187/v1
[5] https://doi.org/10.21203/rs.3.rs-3730125/v1