Broadband nanodielectric spectroscopy by means of amplitude modulation electrostatic force microscopy (AM-EFM)
2011
Schwartz, G.A. | Riedel, C. | Arinero, R. | Tordjeman, Ph | Alegría, A. | Colmenero, J.
In this work we present a new AFM based approach to measure the local dielectric response of polymer films at the nanoscale by means of Amplitude Modulation Electrostatic Force Microscopy (AM-EFM). The proposed experimental method is based on the measurement of the tip–sample force via the detection of the second harmonic component of the photosensor signal by means of a lock-in amplifier. This approach allows reaching unprecedented broad frequency range (2–3×10⁴Hz) without restrictions on the sample environment. The method was tested on different poly(vinyl acetate) (PVAc) films at several temperatures. Simple analytical models for describing the electric tip–sample interaction semi-quantitatively account for the dependence of the measured local dielectric response on samples with different thicknesses and at several tip–sample distances.
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