  The impact of Bi implantation on the conductivity and the thermopower of
amorphous chalcogenide films is investigated. Incorporation of Bi in Ge-Sb-Te
and GeTe results in enhanced conductivity. The negative Seebeck coefficient
confirms onset of the electron conductivity in GeTe implanted with Bi at a dose
of 2x1016 cm-2. The enhanced conductivity is accompanied by defect accumulation
in the films upon implantation as is inferred by using analysis of the
space-charge limited current. The results indicate that native coordination
defects in lone-pair semiconductors can be deactivated by means of ion
implantation, and higher conductivity of the films stems from additional
electrically active defects created by implantation of bismuth.
