恒撞击力轻敲模式AFM的设计及研究

Design and research of constant percussive force atomic force microscope in tapping mode

在轻敲模式AFM中,利用DMT模型与光探针点衍射理论结合来检测微探针的振动,并对振动信号进行频率域分析,通过检测和控制信号中高次谐波分量使针尖-样品间撞击力保持恒定.测试实验表明,该系统具有结构简单、可测不同材料的样品和对软质材料样品损伤小的优点,其测量重复性可达1%,分辩力可达1～5nm.

Referring to AFM in tapping mode, the vibration of microprobe is detected by using the combination of DMT (Derjaguin-Muller-Toporov) model and light probe point-diffraction theory. The vibration signal is analyzed in frequency domain. The percussive force between the probe point and sample is maintained constant through detecting and controlling the high-order harmonic component of signal. The test experiments show that the system has the advantages of simple configuration, testing different materials and a little damage to the soft material sample. Its measuring repeatability and resolution can be 1% and 1~5nm, respectively.