Controlled growth and Atomic-scale Characterization of Two-dimensional hexagonal boron nitride crystals

•Controlled and reproducible synthesis of atomically thin h-BN crystals with tunable thickness.•Low nucleation and growth rates by precise control of BN precursor feeding-rate.•Comprehensive structure analysis using EM imaging, spectroscopy and diffraction analysis. Two-dimensional (2D) hexagonal boron nitride (h-BN) is a fascinating material for variety of applications such as graphene-based devices, transparent/bendable electronics, and deep ultraviolet emitters. However, its technological applications are contingent upon tunable and scalable growth. Here, we demonstrate reproducible and tunable growth of high-quality h-BN crystals on Cu via chemical vapor deposition (CVD) through a precise control of the BN precursor’s flow during growth. We present synthesis of both epitaxially-grown triangular flakes and large-area continuous films with tunable thickness ranging from monolayer to 11-layer thick. Using a combination of electron microscopy imaging, spectroscopy, and diffraction analysis, we thoroughly study morphology, thickness, chemistry, grain size, and atomic structure of the grown h-BN crystals. This study could pave the way for developing controlled and reproducible growth of high-quality h-BN crystals with tunable thickness and morphology.