The lower limit for time resolution in frequency modulation atomic force microscopy
The lower limit for time resolution in frequency modulation atomic force microscopy
复制标题
调频原子力显微镜时间分辨率下限
DOI：
--
复制
发表时间：
2016
期刊：
影响因子：
--
通讯作者：
P. Grutter
中科院分区：
文献类型：
--
作者：
Z. Schumacher;Andreas Spielhofer;Y. Miyahara;P. Grutter
原子力显微镜 (AFM) 通常可以获取亚纳米长度尺度的结构信息。测量这种长度尺度的时间分辨特性以了解纳米尺度的动力学仍然是一个难以实现的目标。我们对 AFM 时间分辨率的下限进行了一般分析。我们的研究结果表明，AFM 的时间分辨率最终受到 AFM 众所周知的热极限的限制，而不是像人们经常提出的那样受到力传感悬臂梁的机械响应时间的限制。我们演示了一种通用的泵浦探针方法，使用悬臂作为响应平均信号的检测器。该方法可应用于任何激励信号，例如电、热、磁或光。该方法的实验实施使我们能够使用谐振频率为 280 kHz 的悬臂来测量低温生长的 GaAs 中~1 ps 的光载流子衰减时间。
Atomic force microscopy (AFM) routinely achieves structural information in the sub-nm length scale. Measuring time resolved properties on this length scale to understand kinetics at the nm scale remains an elusive goal. We present a general analysis of the lower limit for time resolution in AFM. Our finding suggests the time resolution in AFM is ultimately limited by the well-known thermal limit of AFM and not as often proposed by the mechanical response time of the force sensing cantilever. We demonstrate a general pump-probe approach using the cantilever as a detector responding to the averaged signal. This method can be applied to any excitation signal such as electrical, thermal, magnetic or optical. Experimental implementation of this method allows us to measure a photocarrier decay time of ∼1 ps in low temperature grown GaAs using a cantilever with a resonance frequency of 280 kHz.