  The impact of Bi implantation on the conductivity and the thermopower of
GeTe, Ge-Sb-Te, and Ga- La-S films is investigated. The enhanced conductivity
appears to be notably sensitive to a dose of an implant. Incorporation of Bi in
amorphous chalcogenide films at doses up to 1x1015 cm-2 is seen not to change
the majority carrier type and activation energy for the conduction process.
Higher implantation doses may reverse the majority carrier type in the studied
films. Electron conductivity was observed in GeTe films implanted with Bi at a
dose of 2x1016 cm-2. These studies indicate that native coordination defects
present in amorphous chalcogenide semiconductors can be deactivated by means of
ion implantation. A substantial density of implantation-induced traps in the
studied films and their interfaces with silicon is inferred from analysis of
the space-charge limited current and capacitance-voltage characteristics taken
on Au/amorphous chalcogenide/Si structures.
