Acta Physica Sinica, Volume. 69, Issue 2, 027803-1(2020)
Fig. 1. Schematic of s-SNOM. An infrared light is focused between the sample and the probe tip, which oscillate vertically with frequency
and amplitude
Fig. 2. Raman spectra of graphene on Cu substrate. The Lorentzian shape of 2D peak manifested that it is a monolayer graphene. Absence of D peak indicated its defect-free and high-quality nature.生长在铜衬底上的石墨烯拉曼光谱2D峰呈现了单个的洛伦兹峰型, 表明是单层石墨烯; D峰没有出现, 表明是无缺陷的高质量石墨烯
Fig. 3. s-SNOM images of a h-BN/Cu step: (a) Different tip positions when the tip is scanned across a step. ① and ④ are the tip positions far away from the step, ② and ③ are the positions where a peak (corresponding to the formation of two hot-spots) and a dip appear in the s-SNOM signal, respectively. The tip and the step are shown in proportion. Red circle drew on the tip represents its apex with diameter of
Fig. 4. s-SNOM images of two graphene/Cu samples with similar surface step geometries. In both cases, left panel: topography (upper) and s-SNOM image (lower); right panel: line-profiles of topography (upper) and s-SNOM line-profiles (lower) corresponding to the blue solid lines in left panel. (a) Case 1 (peak-dip): step height of about 5.3 nm and width of about 50 nm. Signal peak and dip appear corresponding to the lower and upper edge of the step, respectively; (b) Case 2 (peak): step height of about 5.5 nm and width of about 55 nm. Only a signal peak appears corresponding to the lower edge of the step.衬底台阶几何相近的两个石墨烯/铜样品的s-SNOM成像. 两种情况中, 左侧: 形貌(上)和s-SNOM成像(下); 右侧: 左侧图中蓝色实线对应的形貌(上)和s-SNOM信号(下) (a) 情况一, 台阶高度和宽度分别约为 5.3 nm和50 nm, 峰值和谷值分别对应台阶下方和下方边缘; (b)情况二, 台阶高度和宽度分别约为 5.5 nm和55 nm, 仅出现一个对应于台阶下方边缘的峰值
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Gui Cen, Zhi-Bin Zhang, Xin-Yu Lü, Kai-Hui Liu, Zhi-Qiang Li.
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Received: Oct. 9, 2019
Accepted: --
Published Online: Nov. 9, 2020
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