DOPING OF C-60 FILMS AFTER ION-IMPLANTATI ON

With C60 films, ion implantation of inert ions (argon) gives rise to c onduction processes (sigma > 10(-4) OMEGA-1 cm-1) related to degradati on only in the case where implantation is performed at a high temperat ure (T = 560 K); no sample degeneracy (sigma < 10(-4) OMEGA-1 cm-1) ap pears after argon implantation at room temperature, but doping effects (sigma almost-equal-to 1 OMEGA-1 cm-1) are obtained after implantatio n at room temperature with chemically active ions; with a fluence of t he order of 10(15) ions cm-2, the thermoelectric power then appears ne gative with potassium or phosphorus ions, and positive with bromine or boron ions.