Scanning probe microscopes (SPM) allow scientists to image, characterize and even manipulate material structures at exceedingly small scales including features of atomic proportions. A wide variety of material structures and properties can be studied such as man-made and natural systems, including biological systems. The family of scanning probe microscopes uses no lenses, but rather a probe that interacts with the sample surface. The type of interaction measured between the probe tip and the sample surface defines the type of scanning probe microscope being used. Since the invention of the first scanning tunneling microscope by Heinrich Rohrer and Gerd Binning in 1981, scanning probe microscopy has enabled a burst of nanotechnology achievements that includes the manipulation and arrangement of individual atoms on a surface. This module introduces the theory and application of these nanotechnology tools. 

Key concepts:

  • Operational principles of scanning probe microscopes
  • Theory and fundamental principles of scanning tunneling microscopy (STM) and atomic force microscopy (AFM)
  • The "family" of scanning probe microscopes, including microscopes that measure adhesion energy, friction, magnetic domains, and surface elasticity
  • Interaction forces between atoms and between surfaces
  • Innovation of SPM
  • Design principles of scanning probe tips 
  • Operation of a virtual atomic force microscope (AFM)

Learning Objectives:

After completing this module, you will be able to:
  • Explain the principles of operation of AFM and STM
  • Describe how the force curve results in cantilever deflections that can be interpreted in topographical images 
  • Explain how the force curve can be interpreted using the Lennard-Jones Potential model
  • Explain how the exponential dependency of tunneling current allows for atomic resolution of conductive material structure
  • List at least four types of SPM and what types of material properties can be visualized and measured with each
  • Describe how the various instrumental parameters affect the quality of the SPM image
  • Describe the events that lead to the invention of the scanning probe microscope
In addition to addressing the needs of students at the beginning years of college, this module also addresses the following National Science Education Standards for grades 11-12:

Physical Science Content Standard B

  • Structure and properties of matter
  • Motions and forces
  • Interactions of energy and matter
Science and Technology Content Standard E
  • Abilities of technological design
  • Understandings about science and technology
Science in Personal and Social Perspectives Content Standard F
  • Science and technology in local, national, and global challenges
Nature and History of Science Content Standard G
  • Historical perspective