Kinetic Wulff-shaped heteroepitaxy of phase-pure 2D perovskite heterostructures with deterministic slab thickness

Abstract

The kinetic Wulff shape, determined by the crystal structure and growth rates of different crystal facets, is ubiquitous in classical crystal growth. However, its utilization for heterostructure integration remains largely unexplored. Here we report the discovery of kinetic Wulff-shaped heteroepitaxial growth in halide perovskites, which enables the realization of well-defined phase-pure 2D halide perovskite epitaxial heterostructures with deterministic slab thickness (n = 1–3). This approach allows modulation of the interfacial lattice mismatch from 0% to >11%. Two-domain and complex heterostructures synthesized using this approach have well-defined chemical compositions and electronic structures that may enable the development of ultranarrow domains (less than the de Broglie wavelength of carriers) for solution-processed lateral quantum wells and superlattices. Finally, devices based on these heterostructures demonstrate substantial rectification ratios and reliable switching behaviours under optical or electrical inputs. This study presents the universality of kinetic Wulff-shaped epitaxy in achieving 2D halide perovskite epitaxial heterostructures with high phase purity. Kinetic Wulff-shaped heteroepitaxial growth in halide perovskites enables the realization of well-defined 2D halide perovskite epitaxial heterostructures with deterministic slab thickness (n = 1–3) and high phase purity. Optoelectronic devices based on these heterostructures demonstrate substantial rectification ratios and reliable switching behaviours under optical or electrical inputs.