Park Keunhan, Lee Jungchul, Zhang Zhuomin M, King William P
Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
Rev Sci Instrum. 2007 Apr;78(4):043709. doi: 10.1063/1.2721422.
This article describes tapping mode atomic force microscopy (AFM) using a heated AFM cantilever. The electrical and thermal responses of the cantilever were investigated while the cantilever oscillated in free space or was in intermittent contact with a surface. The cantilever oscillates at its mechanical resonant frequency, 70.36 kHz, which is much faster than its thermal time constant of 300 micros, and so the cantilever operates in thermal steady state. The thermal impedance between the cantilever heater and the sample was measured through the cantilever temperature signal. Topographical imaging was performed on silicon calibration gratings of height 20 and 100 nm. The obtained topography sensitivity is as high as 200 microVnm and the resolution is as good as 0.5 nmHz(1/2), depending on the cantilever power. The cantilever heating power ranges 0-7 mW, which corresponds to a temperature range of 25-700 degrees C. The imaging was performed entirely using the cantilever thermal signal and no laser or other optics was required. As in conventional AFM, the tapping mode operation demonstrated here can suppress imaging artifacts and enable imaging of soft samples.
本文介绍了使用加热式原子力显微镜（AFM）悬臂的轻敲模式原子力显微镜。在悬臂在自由空间中振荡或与表面进行间歇接触时，对悬臂的电学和热学响应进行了研究。悬臂以其机械共振频率70.36 kHz振荡，该频率比其300微秒的热时间常数快得多，因此悬臂在热稳态下运行。通过悬臂温度信号测量悬臂加热器与样品之间的热阻抗。在高度为20和100纳米的硅校准光栅上进行形貌成像。根据悬臂功率，获得的形貌灵敏度高达200微伏/纳米，分辨率高达0.5纳米/赫兹（1/2）。悬臂加热功率范围为0 - 7毫瓦，对应温度范围为25 - 700摄氏度。成像完全使用悬臂热信号进行，无需激光或其他光学元件。与传统原子力显微镜一样，此处展示的轻敲模式操作可以抑制成像伪像并实现对软样品的成像。
