Effect of tip geometry on contrast and spatial resolution of the near-field microwave microscope
Effect of tip geometry on contrast and spatial resolution of the near-field microwave microscope
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DOI：
10.1063/1.2234801
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发表时间：
2006-08-15
影响因子：
3.2
通讯作者：
Anlage, Steven M.
中科院分区：
文献类型：
--
作者：
Imtiaz, Atif;Anlage, Steven M.
近场扫描微波显微镜（NSMM）可以在远短于自由空间波长（lambda）的长度尺度上对材料性质进行定量成像。在这里，我们报告了一项研究的影响，尖端的几何形状上的NSMM信号。这种特殊的NSMM利用扫描隧道显微镜（STM）进行距离跟踪控制。我们系统地研究了许多市售的STM尖端，发现它们在宏观尺度上具有圆锥形结构，在尖端的顶点处具有嵌入的球体（半径为r（球体））。研究中使用的r（球）值范围为0.1至12.6 μ m。具有较大r（球体）的尖端显示出与NSMM的良好信号对比度[如通过隧穿高度和远离样品2 μ m之间的频移（Δ f）信号所测量的]。例如，与r（sphere）=0.55 μ m的尖端的85 kHz相比，r（sphere）=8 μ m的尖端的信号对比度为1000 kHz。然而，大的r（球）提示扭曲的地形特征，通过STM获得。一个理论模型是用来理解的尖端样品的相互作用。该模型定量地解释了测量到的质量因子（Q）的变化作为体铜和硅样品的高度的函数。(c)2006年，美国物理学会。
The near-field scanning microwave microscope (NSMM) can quantitatively image materials properties at length scales far shorter than the free space wavelength (lambda). Here we report a study of the effect of tip geometry on the NSMM signals. This particular NSMM utilizes scanning tunneling microscopy (STM) for distance-following control. We systematically examined many commercially available STM tips and found them to have a conical structure on the macroscopic scale, with an embedded sphere (of radius r(sphere)) at the apex of the tip. The r(sphere) values used in the study ranged from 0.1 to 12.6 mu m. Tips with larger r(sphere) show good signal contrast [as measured by the frequency shift (Delta f) signal between tunneling height and 2 mu m away from the sample] with NSMM. For example, the tips with r(sphere)=8 mu m give signal contrast of 1000 kHz compared to 85 kHz with a tip of r(sphere)=0.55 mu m. However, large r(sphere) tips distort the topographic features acquired through STM. A theoretical model is used to understand the tip-to-sample interaction. The model quantitatively explains the measured change in quality factor (Q) as a function of height over bulk copper and silicon samples. (c) 2006 American Institute of Physics.