Wagner R, Woehl T J, Keller R R, Killgore J P
Material Measurement Lab, National Institute of Standards and Technology, Boulder, Colorado 80305, USA.
Appl Phys Lett. 2016 Jul 25;109(4). doi: 10.1063/1.4960192. Epub 2016 Jul 29.
The response time of an atomic force microscopy (AFM) cantilever can be decreased by reducing cantilever size; however, the fastest AFM cantilevers are currently nearing the smallest size that can be detected with the conventional optical lever approach. Here, we demonstrate an electron beam detection scheme for measuring AFM cantilever oscillations. The oscillating AFM tip is positioned perpendicular to and in the path of a stationary focused nanometer sized electron beam. As the tip oscillates, the thickness of the material under the electron beam changes, causing a fluctuation in the number of scattered transmitted electrons that are detected. We demonstrate detection of sub-nanometer vibration amplitudes with an electron beam, providing a pathway for dynamic AFM with cantilevers that are orders of magnitude smaller and faster than the current state of the art.
通过减小悬臂尺寸可以降低原子力显微镜（AFM）悬臂的响应时间；然而，目前最快的AFM悬臂已接近采用传统光学杠杆方法所能检测到的最小尺寸。在此，我们展示了一种用于测量AFM悬臂振荡的电子束检测方案。振荡的AFM针尖垂直于并位于固定聚焦的纳米尺寸电子束的路径中。当针尖振荡时，电子束下方材料的厚度发生变化，导致检测到的散射透射电子数量出现波动。我们展示了用电子束检测亚纳米级振动幅度，为动态AFM提供了一条途径，其悬臂比当前技术水平小几个数量级且速度更快。
