Atomic-resolution HRTEM and STEM observations were carried out on a JEOL JEM-ARM300F instrument equipped with a cold field emission electron gun and a spherical aberration (Cs) corrector at an acceleration voltage of 80 kV, under 1 × 10 -5 Pa in the specimen column. Typically, we adjusted the Cs value to 1 μm. All HRTEM images were recorded with an exposure time of 4 s on a Complementary Metal-Oxide-Semiconductor (CMOS) camera (Gatan OneView, 4096 × 4096 pixels). In ADF STEM imaging, the probe size was 0.07 nm, the convergence angle was 32 mrad, and the inner and outer collection angles were 45 and 180 mrad, respectively. Although the operated voltage appears to be higher than the knock-on radiation damage threshold reported for h-BN (78 kV), we did not observe any radiation damage during the TEM observations. Image processing including the fast Fourier transformation (FFT) and inverse FFT (IFFT) was carried out by Gatan Digital Micrograph.