Noise in NC-AFM measurements with significant tip-sample interaction
Autor(en): | Luebbe, Jannis Temmen, Matthias Rahe, Philipp Reichling, Michael |
Stichwörter: | amplitude noise; ATOMIC-FORCE MICROSCOPY; cantilever stiffness; closed loop; detection system noise; frequency shift noise; Materials Science; Materials Science, Multidisciplinary; Nanoscience & Nanotechnology; non-contact atomic force microscopy (NC-AFM); Physics; Physics, Applied; Q-factor; RESOLUTION; Science & Technology - Other Topics; spectral analysis; THERMAL NOISE; tip-sample interaction | Erscheinungsdatum: | 2016 | Herausgeber: | BEILSTEIN-INSTITUT | Journal: | BEILSTEIN JOURNAL OF NANOTECHNOLOGY | Volumen: | 7 | Startseite: | 1885 | Seitenende: | 1904 | Zusammenfassung: | The frequency shift noise in non-contact atomic force microscopy (NC-AFM) imaging and spectroscopy consists of thermal noise and detection system noise with an additional contribution from amplitude noise if there are significant tip-sample interactions. The total noise power spectral density D-Delta f(f(m)) is, however, not just the sum of these noise contributions. Instead its magnitude and spectral characteristics are determined by the strongly non-linear tip-sample interaction, by the coupling between the amplitude and tip-sample distance control loops of the NC-AFM system as well as by the characteristics of the phase locked loop (PLL) detector used for frequency demodulation. Here, we measure D-Delta f(f(m)) for various NC-AFM parameter settings representing realistic measurement conditions and compare experimental data to simulations based on a model of the NC-AFM system that includes the tip-sample interaction. The good agreement between predicted and measured noise spectra confirms that the model covers the relevant noise contributions and interactions. Results yield a general understanding of noise generation and propagation in the NC-AFM and provide a quantitative prediction of noise for given experimental parameters. We derive strategies for noise-optimised imaging and spectroscopy and outline a full optimisation procedure for the instrumentation and control loops. |
ISSN: | 21904286 | DOI: | 10.3762/bjnano.7.181 |
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