Structural transformations induced by swift heavy ions in polysiloxanes and polycarbosilanes

High-resolution electron microscopy in connection with electron energy filt ered microscopy is used for evidencing the precipitation of free C clusters in polysiloxanes and polycarbosilanes, responsible for the hardening and l uminescence of these classes of inorganic polymers after ion irradiation. W hile during irradiation with 3 MeV Au ions randomly distributed carbon clus ters are formed, in the case of irradiation with 100 MeV Au ions, the carbo n clusters are aligned along tubular ion tracks without forming continuous wires. Contrary to observations in some other polymers and semiconductors, no tubular voids or crystallization of amorphous SiC were found. It is conc luded that in both cases the carbon precipitation is due to a solid state t ransformation induced by electronic excitations.