压电探针应用于原子力显微镜液体成像的研究

Improved Atomic Force Microscope Imaging in Liquid with Active Probe

研究了采用微悬臂梁上集成的ZnO压电薄膜作为微驱动的探针的直接激振方法，比较了间接激振和直接激振方法下探针在液体中的振动性能，以标准生理溶液中的海拉细胞为样品，对原子力显微镜在液体环境下轻敲模式的成像性能进行了实验研究．研究表明，采用压电探针的直接激振方法在探针振动的幅频曲线中仅有单一谐振峰，可以避免在压电陶瓷管激振方法下由液体振动造成的寄生谐振峰，因此使用压电探针不仅提高了探针振动频率的控制精度，而且减小了针尖对样品的损坏，还提高了仪器的带宽和成像速度．对于512×512点阵和60μm×60μm范围的图像，使用该方法可将采集速度由原来的2～3min／帧提高到15-20s／帧，并且扫描速度的提高对原子力显微镜在动态过程中的研究有着重要的参考价值．

Deposited ZnO thin film on the probe microcantilever as an actuator, a new direct actu ation method was proposed and compared with the traditional piezotube actuation method. An experimental investigation to atomic force microscope tapping-mode imaging properties with Hella cells in standard physiological solution was carried out. It is indicated that only a single resonance peak appears in the amplitude versus frequency curve without spurious resonance peaks during the procedure. The direct actuation enables to improve the tuning accuracy, weaken the possible sample damage by the tip, and enhance the atomic force microscope bandwidth and imaging rate. For an image with 512×512 data set and 60μm×60μm scan scale, the imaging rate is accelerated from 2-3 min to 15-20 s per frame to show the application significance.