High-resolution imaging of heterogeneous surfaces with multifunctional NSOM

Imaging of surfaces and structures by NSOM has matured and is routinely used for studies ranging from biology to materials science. In the present paper, new developments will be emphasized that have resulted from the incorporation of a new technique for shear force feedback control of the scanning tip. The new technique involves the use of a quartz crystal tuning fork with the microscope, and this provides an open architecture for scanning tips. Thus not only is the normal optical contrast imaging done concurrently with topography imaging with optical fibers, but now one may substitute other tips such as nanoelectrodes for electrochemical imaging of reactive surfaces in concurrence with in-situ topography imaging. The modified instrument is now a multifunctional microscope that has many diverse applicationss.