Investigation of nonlinear oscillations in the gas discharge-semiconductor system: effect of different fluid modelling approaches

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2018

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Yeşil, Cihan

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The work deals with the study of nonlinear oscillations in a system, consisted of planar glow discharge layer, coupled to a high-ohmic semiconductor layer. The whole system is sandwiched between two planar electrodes, to which the DC voltage is applied. The discharge models are developed in Comsol Multiphysics (v5.2), and based on ﬂuid description of plasma, with drift-diﬀusion approximation for charged particle ﬂuxes. Numerical tests are carried out for the discharge in Nitrogen, with GaAs semiconductor layer. We ﬁrst derived and tested three diﬀerent ﬂuid models for DC glow discharge: the "simple" model, where the ionization is deﬁned by the Townsend approximation, and two "extended" models with more detailed sets of plasma-chemical reactions. Accuracy and reliability of these models are analyzed by making comparison between the computed and experimental current-voltage characterics. Then, these models are applied to numerical investigation of the gas discharge-semiconductor system. First, the homogeneous stationary states of the system are identiﬁed. Then, the analysis of these states allows to develop bifurcation curves in the parameter space, separating the region where the plasma is stable from the region where it performs the homogeneous oscillations. Comparison with the experimental data allows to determine the accuracy and the ranges of applicability of diﬀerent modelling approaches.

Subject Keywords

Glow discharges., Nonlinear theories., Oscillations.

URI

http://etd.lib.metu.edu.tr/upload/12622219/index.pdf
https://hdl.handle.net/11511/27358

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Graduate School of Natural and Applied Sciences, Thesis

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Citation Formats

C. Yeşil, “Investigation of nonlinear oscillations in the gas discharge-semiconductor system: effect of different fluid modelling approaches,” M.S. - Master of Science, Middle East Technical University, 2018.