Electronic properties of semiconducting poly(ferrocenylsilane) thin films with vapor-phase iodine diffusion doping

We report diffusion doping of the semiconducting polymer poly (ferrocenylsi lanes), or PFS. We have obtained a steady-state conductivity change of grea ter than eight orders of magnitude effected through iodine vapor doping of PFS. The sign of thermoelectric power measurements indicates p-type conduct ivity. The conductivity exhibits an activation energy of DeltaE = (0.45-0.6 5) eV for moderately-doped samples and DeltaE = (0.8-0.99) eV for heavily-d oped samples. We report sample photoconductivity, which we find to be princ ipally of bolometric origin. We also study the evolution of electrical prop erties over time: during several days after fabrication, the samples exhibi t an irreversible decrease in conductivity which may be attributable to par tial iodine desorption. After this aging process, especially noticeable in heavily doped material, the sample properties stabilize, suggesting promise in a range of prospective device applications. (C) 2001 Kluwer Academic Pu blishers.