| AVS 56th International Symposium & Exhibition | |
| Electronic Materials and Processing | Wednesday Sessions |
| Session EM-WeM |
| Session: | Organic & Molecular Electronics |
| Presenter: | F. Martin, Lawrence Berkeley National Laboratory |
| Authors: | F. Martin, Lawrence Berkeley National Laboratory B. Hendriksen, Lawrence Berkeley National Laboratory A.J. Katan, Lawrence Berkeley National Laboratory C. Mauldin, University of California, Berkeley J.M.J. Frechet, Lawrence Berkeley National Laboratory M. Salmeron, Lawrence Berkeley National Laboratory |
| Correspondent: | Click to Email |
We investigated the effect of crystallinity and grain boundaries on the conductivity of Langmuir-Blodgett oligothiophene monolayers using Current-Sensing Atomic Force Microscopy (CS-AFM).
We used the AFM tip as a tool to inject charges and manipulate the crystalline monolayer. We found that passing electrical current locally from the conductive AFM tip led to reversible charging of the native SiO2 layer supporting the film as far as microns away from the charge injection point. This effect, due to charge spreading through the crystalline monolayer, was used to image conduction pathways and study the effect of grain boundaries on the resistivity of the monolayer.
In addition, we found that scanning manipulation at loads in the order of 100nN lead to a 5 fold decrease of the monolayer conductivity in CS-AFM. Subsequent molecular resolution AFM revealed that the degree of crystalline order in manipulated regions of the monolayer had strongly decreased, offering a direct proof of the correlation between order and conductivity in organic monolayers.