Direct Synthesis of Atomically Thin High-κ Bi<sub>2</sub>SeO<sub>5</sub> and Derivatives as a Single-Crystalline Dielectric.
basic_science · Level V
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- Record sourced from PubMed, PMID 41848313.
- Also identified by DOI 10.1021/acs.nanolett.5c05965.
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Abstract
Two-dimensional (2D) materials hold great potential for next-generation electronics. However, the synthesis of compatible dielectrics with a high dielectric constant (κ) presents a critical bottleneck for realizing high-performance field-effect transistors (FETs). Here, we report the direct synthesis of atomically thin Bi<sub>2</sub>SeO<sub>5</sub> single-crystalline by a flux-assisted growth (FAG) method. Leveraging the confined thin molten flux, Bi<sub>2</sub>SeO<sub>5</sub> flakes with thicknesses down to 3.9 nm, lateral sizes up to ∼0.5 mm, and a dielectric constant of ∼15 are achieved. Furthermore, two novel 2D dielectrics of Bi<sub>2</sub>Se<sub>1-<i>x</i></sub>Na<sub><i>y</i></sub>O<sub>5-<i>z</i></sub> (BSO-Na) and Bi<sub>2</sub>Se<sub>1-<i>x</i></sub>O<sub>5-<i>y</i></sub>I<sub><i>z</i></sub> (BSO-I) with maximum lateral sizes of 0.7 and 0.2 mm are obtained by a one-step heterogeneous atom doping strategy, enabling dielectric tunability. In MoS<sub>2</sub> FETs, FAG-grown Bi<sub>2</sub>SeO<sub>5</sub> enables superior electrostatic control, achieving an on/off ratio exceeding 10<sup>7</sup> and a minimum subthreshold swing of 62.7 mV/dec. This work presents a scalable method for producing high-quality high-κ dielectrics and a broadly applicable strategy for the compositional engineering of dielectric systems.