【Substrate Papers】Molecular beam epitaxy of ferroelectric ScAlN on β-Ga₂O₃ substrates

      Researchers from Peking University have published a dissertation titled " Molecular beam epitaxy of ferroelectric ScAlN on β-Ga₂O₃ substrates " in Applied Physics Letters.

Abstract

      We demonstrate the epitaxial integration of ferroelectric ScAlN thin films on β-Ga₂O₃ substrates via molecular beam epitaxy without any buffer layers, enabled by surface pre-nitridation. The resulting ScAlN films exhibit robust ferroelectricity, characterized by large apparent remanent polarization (>150 lC/cm²), good retention (>10⁵ s), and minimal fatigue observed up to 10⁵ switching cycles. High-resolution x-ray photoelectron spectroscopy reveals a type-II band alignment at the ScAlN/β-Ga₂O₃ heterointerface, with extracted valence and conduction band offsets of 0.5 and 1.0eV, respectively. These results establish an oxide/nitride heterostructure platform that combines the intrinsic ferroelectricity of ScAlN with the ultra-wide bandgap and photosensitive properties of β-Ga₂O₃, offering compelling opportunities for next-generation nonvolatile memory, photodetection, and optoelectronic synaptic devices.

DOI：

https://doi.org/10.1063/5.0324858