With the expanding use of the scanning tunneling microscope, the technology is developing into other scanning near field microscopes, microscopes whose resolution is determined by the size of the probe, not by some wavelength. The first available “son of STM” will be the atomic force microscope (AFM), a very low force profilometer which has atomic resolution and can profile non-conducting surfaces. The hope is that this microscope may find more applications in biology than the scanning tunneling microscope (STM), which requires a conducting or very thin sample.In the past five years, the STM has progressed from curiosity to everyday lab tool, imaging surfaces with scans from a few nanometers up to 100 microns. When compared to an SEM, the STM has the advantages of higher resolution, lower cost, operation in air or liquid, real three-dimensional output, and small size. The disadvantages are smaller scan size, slower scan speeds, fewer spectroscopic functions and, of course, not as many of the nice features of the more mature electron microscopes. The AFM has similar features to the STM except that the detector and profiling tips are more complicated and more difficult to operate—disadvantages that will decrease with time.
Near-Field Manipulation in a Scanning Tunneling Microscope Junction with Plasmonic Fabry-Pérot Tips