Understanding the mechanism of heteroepitaxy in perovskite halides

Abstract

Van der Waals and remote epitaxy are emergent epitaxial growth technologies expected to bring rich opportunities in designing advanced electronics and optoelectronics that are liberated from the constriction of lattice-match concept. The weak film-substrate interaction allows the post transfer of the film component to other substrates which could be chemically/structurally vastly different from the film. In this thesis, I first demonstrate the van der Waals and remote epitaxy of LiNbO3 films on muscovite mica and graphene-buffered sapphire respectively, by pulsed laser deposition. I then show the remote epitaxy of CsPbBr3 on rock salts, and ZnO on GaN using vapor deposition and hydrothermal approaches, respectively. Using spectroscopy, microscopy, diffraction, and transport characterizations, I reveal the nucleation and growth kinetics of remotely epitaxial thin films. I then show the feasibility of the transfer and integration of remotely epitaxial perovskite film for developing prototype flexible photodetectors. Finally, I demonstrate the use of heteroepitaxy technique to break inversion symmetry of perovskite halides for tuning their circular photogalvanic effect. The enriched understanding of the growth mechanism of perovskite-based heterostructures and their optoelectronic properties helps design future computing and sensing devices.