Seed-assisted growth of large-area β'-In2Se3 ferroelectric thin films

Abstract

The recent discovery of two-dimensional ferroelectric semiconductors, such as In₂Se₃, has opened promising avenues for ultra-thin micro-nano electronic devices, and energy-efficient neuromorphic systems. Despite these exciting prospects, achieving large-area, high-quality, layer-controlled growth of single-phase In₂Se₃ remains a considerable challenge. In this study, we present a seed-assisted strategy for growing uniform, centimeter-scale β'-In₂Se₃ thin films by mixing In₂O₃ and In₂Se₃ single crystals in a specific ratio. The resulting β'-In₂Se₃ phase and composition are verified through X-ray diffraction, transmission electron microscopy, and Raman spectroscopy. Furthermore, the ferroelectric properties and domain configurations have been characterized by using polarized light microscopy and piezoresponse force microscopy. Importantly, we investigate the topological evolution of ferroelectric domains across films with varying thicknesses, revealing insights into domain structure modulation. This growth method not only provides a scalable route for synthesizing similar ferroelectric two-dimensional materials but also a possibility for the practical integration of β'-In₂Se₃ in optoelectronic, neuromorphic, and other advanced micro-nano electronic applications.