Dark and Photoconductivity Behaviors of Amorphous and Crystalline C₆₀ Films

Abstract

Deposition and in-situ electrical conductivity measurement of C 60 thin films were conducted under high-vacuum conditions to evaluate the intrinsic electrical properties of C 60 films without ambiguity due to surface contamination. Amorphous and polycrystalline films were deposited by vacuum evaporation of C 60 powders onto fused silica glass, and cleaved NaCl(100) substrates, respectively, on which Al electrodes were deposited in advance. The film conductivity measured in-situ is highly reproducible and strongly dependent on the crystallinity not only in the absolute values of conductivity and its activation energy, but also in the behaviors under light irradiation and air exposure.