CHANGES OF THE OPTICAL AND ELECTRICAL-PROPERTIES OF PLASMA POLYMER-METAL COMPOSITE FILMS DURING THERMAL ANNEALING

The electrical and optical properties of plasma polymer-metal composit e films prepared by simultaneous plasma polymerization and metal evapo ration depend on the plasma polymer properties and the metal volume pa rt (filling factor). The microstructure of plasma-polymerized films wi th encapsulated silver particles was changed during thermal annealing up to 480 K. Transmission electron microscopy demonstrates the microst ructural changes. The changes of the silver particle size and shape we re analyzed by optical image processing. In one film with continuously varying filling factor, samples with conductivities above and below t he percolation threshold were found after deposition. During the therm al annealing the d.c. conductivity of samples above the percolation th reshold (f >f(c)) decreases from 10(-1) OMEGA-1 cm-1 to 10(-8) OMEGA-1 cm-1. In the UV-VIS-NIR region, the annealing affects the optical pla sma resonance absorption of the metal particles. Relative intensity, h alf-width and spectral position of the transmission minima were change d. By consideration of the optical image processing results, the spect ral shift of the plasma resonance was simulated with effective-medium theories.