AFM针尖“突跳”研究

Study on “Jump-to-contact” of Atomic Force Microscopy

为了研究原子力显微镜(AFM)“突跳”现象的产生机理,基于经典弹性理论和Lennard-Jones势能定律建立了AFM针尖与样品纳米接触的弹性模型。给出了在AFM针尖逐渐趋近样品表面的过程中,AFM针尖与样品间的粘着力、样品表面的轮廓曲线和样品表面的变形量随AFM针尖与样品表面间距的变化规律。分析了AFM“突跳”现象的产生机理和影响因素。研究表明,AFM“突跳”现象主要是由样品表面在粘着引力的作用下产生拉伸变形并与AFM针尖“突跳”接触引起的。

Based on the classical elastic theory and Lennard-Jones potential, an elastic moclel ot nano-contact between a sphere and a plane was established to investigate the cause of jump-to- contact of atomic force microscopy （AFM）. The variations are obtained of the adhesive force, the contour and the deformation of the sample surface with the AFM tip-sample gap. The results indicate that the sudden jump of the sample surface to the AFM tip is the crucial cause of the jump-to-contact of AFM.