A scanning tunneling microscope (STM) for biological applications: design and performance.

The design of a scanning tunneling microscope (STM) for biological applications, operating at ambient pressure, is described. The STM is combined with an "auxiliary" light microscope to facilitate finding and identifying specimen areas of interest. The performance of the STM has been tested with evaporated gold films and with graphite. We have evaluated evaporated carbon and platinum/carbon films deposited on glass or mica to be used as specimen supports. First applications to biological material coated with a conducting film of platinum/carbon are described.