Isotope-Engineered Hexagonal Boron Nitride Films Synthesized by Plasma-Enhanced Chemical Vapor Deposition from Elemental Boron and Nitrogen Precursors
Hexagonal boron nitride (hBN) is indispensable for next-generation electronics and quantum technologies, yet controlled synthesis of isotopically engineered hBN with macroscopic scalability and atomic-level precision remains challenging. Here, we present a plasma-enhanced chemical vapor deposition (PECVD) method using elemental boron (B) and nitrogen (N) precursors to achieve wafer-scale growth and precise isotopic control of hBN films. High-quality hBN films are synthesized on Cu substrates via optimized B evaporation and N2 plasma activation. The growth mechanism involves an oxygen-mediated pathway for B transport and a layer-by-layer (Frank-van der Merwe) mode for multilayer formation. By employing isotopically enriched B powders (10B and 11B) and N2 gases (14N2 and 15N2), we demonstrate tunable isotopic compositions with phonon mode shifts quantitatively matching harmonic oscillator predictions. Furthermore, we realize unprecedented in-plane h10BN-h11BN heterostructures through dynamic B source switching during growth. This PECVD strategy establishes a transformative synthesis platform merging industrial-scale production capacity with atomic-scale isotopic precision, enabling new opportunities to engineer thermal transport, optical response, and quantum coherence in two-dimensional materials.