声子
材料科学
极化子
纳米尺度
红外线的
近场扫描光学显微镜
氮化硼
红外光谱学
电介质
散射
表面声子
晶界
光学
凝聚态物理
分子物理学
光电子学
化学
纳米技术
微观结构
光学显微镜
扫描电子显微镜
物理
复合材料
有机化学
冶金
作者
Makoto Takamura,Kenji Watanabe,Takashi Taniguchi,Yoshitaka Taniyasu
摘要
Nanoscale evaluation of the number of layers and boundaries in two-dimensional (2D) materials is crucial for understanding relationships between structure and property. Here, using scattering-type scanning near-field optical microscopy, we systematically studied on a nanoscale the infrared spectra and imaging of hexagonal boron nitride (h-BN), an ideal 2D insulating material. We revealed that the main factor determining the infrared amplitude changes at an optical frequency of about 1370 cm−1, corresponding to the in-plane phonon mode of h-BN. At lower frequencies, the amplitude is mainly determined by the local dielectric function of a sample and depends on the number of h-BN layers. At higher frequencies, it is affected by the phonon polariton waves of h-BN, and thus edges and grain boundaries of h-BN can be visualized due to the reflection of the waves at the boundary. The infrared spectra show a shoulder peak at higher frequencies, derived from the resonance with the phonon polaritons, in addition to a peak due to the in-plane phonon mode.
科研通智能强力驱动
Strongly Powered by AbleSci AI