TEMPERATURE INDUCED STRUCTURAL REARRANGEMENTS OF AG/A-C - H COMPOSITE FILMS AND THEIR DC ELECTRICAL-CONDUCTION

Silver doped hydrogenated amorphous carbon (a-C:H) films were prepared in an rf (13.56 MHz) glow discharge onto negatively biased substrates using a butane-argon mixture and a resistively heated boat for silver co-evaporation. Temperature induced structural rearrangements were studied by TEM in connection with the changes of the dc electrical conduction and optical transmission. Qualitative explanation was based on TEM micrographs. It was found that electrical and optical properties showed irreversible change for temperatures above 280°C. The dc electrical conduction of Ag/a-C:H films has been found to be rather complex for high temperatures but for low temperatures it can be described in terms of a theory for granular metals. © 1990.