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 current-sensing AFM combined with an optical pumping laser, was developed in order to investigate the interaction between light and matter in a nanometer-scale tinny structure. The principle of the photoconductive AFM is the measurement of the photocurrent in an individual nanometer-scale structure, and also two-dimensional mapping of the photoelectric property by scanning the conductive cantilever on the surface of a sample. The photoelectric property of an organic thin film with copper phthalocyanine was demonstrated to test the performance of this system. Nanometer-scale point contact photocurrent, point contact current-voltage characteristics and photoconductive imaging could be attained using the system. Photoconductive AFM has the potential to be of use in various fields of nanometer-scale photonics.