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