The thickness dependence of dielectric properties in the plasma polymer thin films

In this study, the results of dielectric spectroscopy of plasma polymerized poly(ethylene oxide) thin films are presented. The films were deposited by plasma assisted physical vapour deposition at radio-frequency plasma discharge power of 5 W. Thicknesses of the films have 20nm,100nm,250nm. Dielectric measurements of the films were performed in the frequency range of 10−1 Hz to 107 Hz and temperature was scanned between 173 K and 353 K. The dielectric constant (ε′) and dielectric loss (ε″) of plasma polymerized poly(ethylene oxide) thin films were calculated by measuring capacitance (C) and dielectric loss factor (tan δ) . It was observed that there were two relaxation mechanisms in the investigated frequency range. These were called as α and β relaxations. These relaxations shifts toward higher frequencies with incresing temperature. Besides, α-relaxation starts to appear at different temperatures. This shows the difference between the polarizability abilities of samples at same temperature and same frequencies. The reason of this behavior can be expressed by dead layer concept which is a result of good adhesion of the bottom layer of plasma polymer to the substrate. By the light of these interpretations, with thinner samples it is possible to have structurally similar thin films like thin films deposited at high plasma power. A thinner film may support more transparent and these thinner films may be effective as coverage of optical devices such as lenses, visors etc.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author