Electrical properties of Bi-implanted amorphous chalcogenide films
  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. 
Yanina G. Fedorenko, Mark A. Hughes, Julien L. Colaux, C. Jeynes,   Russell M. Gwilliam, Kevin Homewood, B. Gholipour, J. Ya...
cond-mat.mtrl-sci