品质因数调控技术提高AFM横向分辨力的研究  

Improvement of Lateral Resolution of Tapping Mode AFM in Liquid by Active Control of AFM Microcantilever′s Quality Factor

作　　者：房轩[1] 李艳宁[1] 傅星[1] 胡小唐[1] 

机构地区：[1]天津大学精密测试技术及仪器国家重点实验室,天津300072

出　　处：《天津大学学报》2007年第2期206-209,共4页Journal of Tianjin University(Science and Technology)

基　　金：国家自然科学基金资助项目(50305025;50675152)

摘　　要：液体中轻敲模式下微悬臂梁的低品质因数会限制原子力显微镜的力灵敏度和成像分辨率,品质因数调控技术可以提高品质因数.在分析品质因数调控技术机理的基础上,分别在一般轻敲模式下和有品质因数调控电路支持的轻敲模式下,利用琼脂糖凝胶作为样品,测得力曲线.分析比较这2种情况下的曲线,表明在无品质因数调控时,微悬臂梁的驱动信号的振幅是恒定的,而在有品质因数调控时,微悬臂梁驱动电压随着针尖样品间距的减小而衰减,从而导致针尖-样品间的相互作用力减小,横向分辨力提高.为了验证该分析结果,检测了液体中的蛋白质分子.在有品质因数调控时,很容易获得清晰的蛋白质分子图像,由此证明了上述结论.In liquid, the low quality factor of the microcantilever in tapping mode limits the force sensitivity and imaging resolution of atomic force microscopy （AFM）. Quality factor control technique （Q-control） can control the force sensitivity and imaging resolution by precise adjustment of the microcantilever＇s quality factor. The theory of the quality factor control technique is described in this paper. For experimental study, agarose gel＇s force curves were obtained in tapping mode with and without Q-control. By analyzing these force curves, it is shown that in tapping mode without Q-control the drive signal＇s amplitude is almost constant, whereas in tapping mode with Q-control the drive voltage decays with the decrease of tip-sample distance, resulting in the decrease of tip-sample interaction force and improvement of lateral imaging resolution. Imaging experiments on protein molecules with Q-control showed that clear images of protein molecules were easily obtained.

关 键 词：原子力显微镜 微悬臂梁 品质因数 轻敲模式 

分 类 号：TN16[电子电信—物理电子学]