Electrical measurement on a phthalocyanine Langmuir-Blodgett film: I. Comprehensive studies on the origins of scattering and drift of resistance values

摘要

The semi-conducting properties of an organic Langmuir-Blodgett (LB) film have been investigated using two configurations of LB film and electrodes. The studied material is the copper tetraoctadecyltetrapyridino [3,4-b:3 prime ,4 prime -g:3 double prime ,4 double prime -1:3 triple prime ,4 triple prime -q] porphyrazinium bromide (CuS18). The scattering of resistance values appears to be dependent on the configuration. Films in the `down' configuration (electrodes under the LB film) present resistance values that are less scattered but higher than the ones of films in the `top' configuration (electrodes over the LB film). The good but less reproducible contact which is observed in the `top' configuration is certainly provided by the penetration of gold atoms inside the organic film. Similarly, a study on the factors which influence the stability of organic/inorganic devices suggests that these factors originate from material structural evolution mainly near the shadow area of the electrodes.