Could you pick up a boulder with a pair of tweezers? Could you pick up a piece of hair with a bulldozer? Having the right size tools for the job can be pretty important. When scientists study the nanoscale, they need to use tools that are the right size. To study things that are very, very small, they need very, very small tools.
Scanning probe microscopes are a set of tools with very small parts that help scientists image the nanoscale. Each type of scanning probe microscope involves a very fine probe tip that scans back and forth over a surface. The ability to image individual atoms in scanning probe microscopies can be mimicked with a refrigerator magnet.
The first SPM was the scanning tunneling microscope (STM). STM is limited to surfaces that are electrically conductive. Later, Atomic Force Microscopy (AFM) was invented, which could scan any surface, conductive or not.
Before STM was invented, scientists and engineers could not “see” atoms or atomic scale features. The technique was invented in 1981 by a couple of IBM researchers, Gerd Binnig and Heinrich Rohrer, at the Rueschlikon, Switzerland IBM facility. With the discovery of this technique, scientists could look at the atomic level upward. It came just in time for the semiconductor industry that needed to locate and measure the size and performance of chips.
In 1982 Binnig and Rohrer reported using a STM to see atoms in a silicon sample. For the development of the STM, they won the Nobel Prize in physics in 1986. Binnig, Christoph Gerber (IBM Zurich), and C. F. Quate (Stanford University) are credited with the development of the atomic force microscope (AFM). In 1987 Tom Alrecht was the first to see atoms using a AFM. In 2007 the first cases of identification of atoms in the surface of a material were reported using a AFM. Each element in the alloy was first investigated to determine the amount of interaction there was with the probe. Then atoms of those elements were identified in the surface by “feeling” the atoms with the probe and identifiying the element based on the amount of interaction.
Some of the other forms of scanning probe microscopy include: Magnetic Force Microscopy, MFM; Chemical Force Microscopy, CFM; Scanning Force Micrsocopy, SFM; and Electrostatic or Electric Force Micrsocopy, EFM.