Design and implementation of sequential excitation module for high fidelity piezoresponse force microscopy

Chunlin Song; Boyuan Huang; Jun Feng; Jiangyu Li

doi:10.1063/5.0103580

Design and implementation of sequential excitation module for high fidelity piezoresponse force microscopy

Rev Sci Instrum. 2022 Aug 1;93(8):083707. doi: 10.1063/5.0103580.

Authors

Chunlin Song¹, Boyuan Huang¹, Jun Feng¹, Jiangyu Li¹

Affiliation

¹ Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China and Guangdong Provincial Key Laboratory of Functional Oxide Materials and Devices, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China.

PMID: 36050062
DOI: 10.1063/5.0103580

Abstract

The acquisition of accurate information through a contact resonance mode is critical for mapping weak electromechanical effect reliably by using piezoresponse force microscopy (PFM). However, it is very challenging to track resonance frequency shifting when the contact stiffness from the sample varies significantly. In this work, we have developed a sequential excitation (SE) module to enable high fidelity PFM. A customized discrete frequency sweep signal from an arbitrary waveform generator is used for drive excitation so that resonance frequency tracking is no longer necessary. Furthermore, the AC component of the piezoresponse is sampled by using an oscilloscope instead of using lock-in amplifiers. To accommodate high volume of data acquisition, a fast analysis method is also developed to fit the transfer function of the cantilever efficiently on the fly during scanning. Hardware implementation and data processing are described in detail. The capability of our SE module has been demonstrated on an ordinary PMN-PT film via first and second harmonic PFM, as well as a suspended freestanding MoS₂ membrane that is very challenging to probe due to its substantial variation in contact stiffness.