Grain boundaries are observed and characterized in chemical vapor deposition-grown sheets of hexagonal boron nitride (h-BN) via ultra-high-resolution transmission electron microscopy at elevated temperature. Five- and seven-fold defects are readily observed along the grain boundary. Dynamics of strained regions and grain boundary defects are resolved. The defect structures and the resulting out-of-plane warping are consistent with recent theoretical model predictions for grain boundaries in h-BN.
The defect structure of single layer sheets of CVD synthesized hexagonal boron nitride was imaged at atomic resolution using the Fusion system. At temperatures of 450° C, grain boundaries and associated defects were studied. The defects evolved over time, and the dynamics were captured in sequential images. The high stability of the Fusion system enabled the collection of this high quality data. All images were taken with the TEAM 0.5 TEM at NCEM/LBNL.