Compensation of Parasitic Capacitance of Quartz Tuning Fork in AFM  

作　　者：Yidai Liu Yidai Liu(Physics Department, Hong Kong University of Science and Technology, Hong Kong, China)

机构地区：[1]Physics Department, Hong Kong University of Science and Technology, Hong Kong, China

出　　处：《Journal of Applied Mathematics and Physics》2023年第5期1404-1413,共10页应用数学与应用物理（英文）

摘　　要：We have built an atomic force microscope using a quartz tuning fork as sensor. The excitation method we adopted, the electrical excitation, introduces stray capacitance into the signal-processing circuit. In this report, we demonstrated a simple but effective method to compensate for this parasitic capacitance by adding a compensator circuit consisting of an inverting amplifier and a capacitor. The capacitor is connected in series with the inverting amplifier and the compensator is connected in parallel with the quartz tuning fork. The resonance curve of the system measured after adding the homemade compensator resembles that of a pure RLC circuit, meaning that the stray capacitance is successfully eliminated. Furthermore, we tried to use our equipment to measure PDMS sample and got clean data. This system can be further combined with confocal microscope and diamond with NV defect to build scanning NV magnetometry.We have built an atomic force microscope using a quartz tuning fork as sensor. The excitation method we adopted, the electrical excitation, introduces stray capacitance into the signal-processing circuit. In this report, we demonstrated a simple but effective method to compensate for this parasitic capacitance by adding a compensator circuit consisting of an inverting amplifier and a capacitor. The capacitor is connected in series with the inverting amplifier and the compensator is connected in parallel with the quartz tuning fork. The resonance curve of the system measured after adding the homemade compensator resembles that of a pure RLC circuit, meaning that the stray capacitance is successfully eliminated. Furthermore, we tried to use our equipment to measure PDMS sample and got clean data. This system can be further combined with confocal microscope and diamond with NV defect to build scanning NV magnetometry.

关 键 词：Atomic Force Microscope Quartz Tuning Fork Stray Capacitance Compensator Circuit PDMS Sample 

分 类 号：TN7[电子电信—电路与系统]