Nanometer-scale photoelectric property of organic thin films investigated by a photoconductive atomic force microscope

A photoconductive:atomic force microscope (AFM), which is a contact mode cu rrent-sensing AFM combined with an optical pumping laser, was developed in order to investigate the interaction between light and matter in a nanomete r-scale tinny structure. The principle of the photoconductive AFM is the me asurement of the photocurrent in an individual nanometer-scale structure, a nd also two-dimensional mapping of the photoelectric property by scanning t he conductive cantilever on the surface of a sample. The photoelectric prop erty of an organic thin film with copper phthalocyanine was demonstrated to test the performance of this system. Nanometer-scale point contact photocu rrent, point contact current-voltage characteristics and photoconductive im aging could be attained using the system. Photoconductive AFM has the poten tial to be of use in various fields of nanometer-scale photonics.