Robust high-κ response in molecularly thin perovskite nanosheets

Size-induced suppression of permittivity in perovskite thin films is a fundamental problem that has remained unresolved for decades. This size-effect issue becomes increasingly important due to the integration of perovskite nanofilms into high-κ capacitors, as well as concerns that intrinsic size effects may limit their device performance. Here, we report a new approach to produce robust high-κ nanodielectrics using perovskite nanosheet (Ca ₂Nb₃O₁₀), a new class of nanomaterials that is derived from layered compounds by exfoliation. By a solution-based bottom-up approach using perovskite nanosheets, we have successfully fabricated multilayer nanofilms directly on SrRuO₃ or Pt substrates without any interfacial dead layers. These nanofilms exhibit high dielectric constant (>200), the largest value seen so far in perovskite films with a thickness down to 10 nm. Furthermore, the superior high-κ properties are a size-effect-free characteristic with low leakage current density (<10 ^-7 A cm^-2). Our work provides a key for understanding the size effect and also represents a step toward a bottom-up paradigm for future high-κ devices.