We demonstrate a nondestructive way to determine the number of layers of hexagonal boron nitride (h-BN) by scattering-type scanning near-field optical microscopy (s-SNOM). The amplitude of s-SNOM near-field signals show a dependence on the number of h-BN layers, which can be explained by a finite dipole model. The layer number estimated by the s-SNOM is consistent with that observed by a transmission electron microscopy. This method also allows us to estimate the domain size of h-BN from the distribution of s-SNOM signals. These results demonstrate that the layer number and its in-plane distribution can be evaluated by s-SNOM with nanoscale spatial resolution.

我们演示了通过散射型扫描近场光学显微镜（s-SNOM）确定六角形氮化硼（h-BN）的层数的无损方式。s-SNOM近场信号的幅度显示出与h-BN层数的相关性，这可以通过有限偶极子模型来解释。s-SNOM估计的层数与透射电子显微镜观察到的层数一致。该方法还允许我们根据s-SNOM信号的分布来估计h-BN的域大小。这些结果表明，层数及其平面内分布可以通过具有纳米级空间分辨率的s-SNOM进行评估。