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P: Fachverband Plasmaphysik

P 11: Complex Plasmas and Dusty Plasmas I

P 11.5: Vortrag

Donnerstag, 2. September 2021, 12:15–12:30, H4

Charge measurement of SiO₂ nanoparticles in an RF-plasma by IR absorption — •Harald Krüger and André Melzer — Institute of Physics, University Greifswald

Dusty plasmas with nanoparticles have drawn increased attention in the last few years. We have performed measurements of the IR absorption of SiO₂ nanoparticles confined in an argon radio-frequency plasma discharge using an FTIR spectrometer. By varying the gas pressure of the discharge and duty cycle of the applied radio-frequency voltage we observed a shift of the absorption peak of SiO₂. We attributed this shift to charge-dependent absorption features of SiO₂. The charge-dependent shift has been calculated for SiO2 particles and from comparisons with the experiment the particle charge has been retrieved. With the two different approaches of changing the gas pressure and altering the duty cycle we are able to deduce a relative change of the particle charge with pressure variations and an absolute estimate of the charge with the duty cycle.