Role of sublimation kinetics of ammonia borane in chemical vapor deposition of uniform, large-area hexagonal boron nitride

Abstract

Hexagonal boron nitride, h-BN, is a critical 2D insulator used as a substrate, gate dielectric, or encapsulation layer for graphene and other 2D materials and their van der Waals heterostructures.It is also promising as an active layer in single-photon emitters and other photonic devices. With chemical formula H 3 N-BH 3 , ammonia borane is the most attractive precursor for up-scalable growth of large-area h-BN, using chemical vapor deposition given its stoichiometric B:N ratio, high stability under ambient conditions, non-toxicity, and high solubility in common solvents.Here, the synthesis of large-area (100 mm × 150 mm) crystalline hexagonal boron nitride layers by thermal activation and decomposition of the precursor ammonia borane is presented. We describe two different reaction pathways for h-BN synthesis, providing evidence for dis-similarities in the sublimation kinetics of ammonia borane and how these differences critically influence the growth of h-BN. This understanding helps us accelerate h-BN production, re-use precursors, and reduce machine runtime, paving the way for upscalability. Moreover, our work provides a consistent unified view explaining the diverse deposition conditions reported in the literature for h-BN grown by CVD using ammonia borane as a precursor.

Dual role of hBN as an artificial solid–electrolyte interface layer for safe zinc metal anodes

“…1d is consistent with the reported value of the E 2g vibrational mode at 1370 cm −1 for monolayer hBN. 44,45 X-ray photoelectron spectroscopy (XPS) is employed to study the chemical state of hBN. Fig.…”

Room-Temperature Emitters in Wafer-Scale Few-Layer Hbn by Atmospheric Pressure Cvd

“…S2 for details). By controlling the solid-state phase transition of AB via heating, it is possible to maximize its volatility and control the sublimation [34,35]. To this end, we carefully controlled the pre-heating stage (in terms of temperature, precursor positioning and time) to release the gaseous precursor at the desired stage of the CVD process.…”