The electroforming effect in polycrystalline fullerene С$_{60}$ films

Long-term exposure of a polycrystalline fullerene С$_{60}$ film in a constant electric field of 1–4 MV/cm produces an electroforming effect manifested by increase in conductivity of the film within several orders of magnitude. After this electroforming, the current–voltage ( I – U ) characteristic shows a high degree of current stability and reproducibility of results. In fields of 10$^5$–10$^6$ V/cm, the I – U characteristics of electroformed films are determined by the space-charge limited current. The concentration ($N_{t}\approx$ 4 $\times$ 10$^{21}$ m$^{-3}$) of carrier traps and their energy ($E_{t}\approx$ 0.176 eV) have been estimated.