Nanoscale Electrical Properties Conductive AFM

SNOM has been applied to map topography and photocurrent of the active layer of some organic photovoltaic devices [63, 64]. However, the reported spatial resolution was only about 200 nm. 

For conductive AFM measurements, the tip was kept in contact with the sample surface while the current through the tip was measured. In contrast to operating in intermittent contact (IC) mode, contact mode is characterized by a strong tip-sample interaction that can lead to destruction of the surface, especially in the case of soft polymer samples. Therefore, the load applied to the tip during C-AFM has to be small enough to reduce sample destruction and, at the same time, it must provide a reliable electric contact. We usually operated with a load of about 10-20 nN. The contact cantilevers used for C-AFM are suitable for operation in IC as well as in contact mode so that nondestructive testing of the sample surface could be performed before and after the C-AFM measurements. C-AFM measurements of the 

PCBM/MDMO-PPV film spin coated from values represent 1.2 nA current variation) and 

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