Amplitude dependence of image quality in atomically-resolved bimodal atomic force microscopy
Amplitude dependence of image quality in atomically-resolved bimodal atomic force microscopy
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DOI：
10.1063/1.4964125
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发表时间：
2016-10-03
影响因子：
4
通讯作者：
Giessibl, Franz J.
中科院分区：
文献类型：
--
作者：
Ooe, Hiroaki;Kirpal, Dominik;Giessibl, Franz J.
在双峰调频原子力显微镜（FM-AFM）中，两个弯曲模态同时被激发。我们展示了在两种模式下的环境条件下KBr（100）的原子分辨图像，显示图像质量和振幅之间有很强的相关性。我们将和振幅定义为两种模态振幅的和。当振幅和大于100pm时，信噪比急剧下降。我们认为这是由于在尖端样品间隙中暂时存在一个或多个水层造成的。这些水层屏蔽了短程相互作用，必须随着每个振荡周期而位移。然而，降低任何一种模式的振幅都会增加噪声。因此，在环境条件下，当两倍振幅之和略小于初级水化层厚度时，信噪比达到最高。AIP出版社出版。
In bimodal frequency modulation atomic force microscopy (FM-AFM), two flexural modes are excited simultaneously. We show atomically resolved images of KBr(100) in ambient conditions in both modes that display a strong correlation between the image quality and amplitude. We define the sum amplitude as the sum of the amplitudes of both modes. When the sum amplitude becomes larger than about 100 pm, the signal-to-noise ratio (SNR) drastically decreases. We propose that this is caused by the temporary presence of one or more water layers in the tip-sample gap. These water layers screen the short range interaction and must be displaced with each oscillation cycle. Decreasing the amplitude of either mode, however, increases the noise. Therefore, the highest SNR in ambient conditions is achieved when twice the sum amplitude is slightly less than the thickness of the primary hydration layer. Published by AIP Publishing.