K. Grytsenko, Y. Kolomzarov, M. Sopinskyy, D. Pekur, A. Kukla
Transparent thin films of polyterafluoroethylene (PTFE) were produced by electron-assisted deposition in vacuum (EVD). A feature of the method is the injection of electrons into a vacuum chamber (P = 10-3 – 10 -4 Torr), where they collide with evaporated organic molecules and stick to them, transferring both energy and negative electric charge. Additional low temperature radio frequency plasma is also used for treatment of molecules in the gas phase. Due to the low pressure, action of the plasma is much gentler than that of classic plasma. The refractive index of PTFE films varied from 1.15 to 1.4, and its anisotropy also was varied with varying deposition conditions. The extinction index varied from 10-3 to 10-5. PTFE films, filled with gold and silver nanoparticles as well as ultra-stable dye-filled PTFE films were produced by co-deposition. Stable polymeric dye films were produced by EVD using several allyl-terminated compounds. Evolution of transmittance during film growth was studied using in situ optical spectroscopy, thus discovering changes in the film structure caused by thickness increase and by deposition conditions. Maximum of plasmon band in metal-filled PTFE and maxima of bands in dye-filled PTFE films depended on filler concentration, filler nature and deposition conditions. Films with required optical spectra have been producing by EVD using in situ optical spectroscopy as a tool for monitoring and correction of deposition conditions in real time. Stable polymer and nanocomposite thin films with specified optical properties are promising for applications in optoelectronic micro- and macro-devices.
