Atomic microscope

An Atomic Microscope or Scanning Tunneling Microscope is, according to Wikipedia, is a powerful instrument for imaging surfaces at the atomic level. The STM can be used not only in ultra high vacuum but also in air, water, and various other liquid or gas ambients, and at temperatures ranging from near zero kelvin to a few hundred degrees Celsius. The STM is based on the concept of quantum tunneling. When a conducting tip is brought very near to the surface to be examined, a bias (voltage difference) applied between the two can allow electrons to tunnel through the vacuum between them. The resulting tunneling current is a function of tip position, applied voltage, and the local density of states of the sample. Information is acquired by monitoring the current as the tip's position scans across the surface, and is usually displayed in image form.

Basic parts needed for an STM include:

• a computer
• a digital-to-analog interface
• analog-to-high-voltage analog amplifiers
• piezo tube (are there any other alternatives for atomic-resolution positioning?)
• mounting hardware
• vibration isolation hardware (cases, rubber feet, bungee cords, etc.)
• tips (there seem to be a wide variety of prices)

Plans

• Juergen Mueller provides detailed plans and schematics (PDF) on his website.
• The University of Münster's Physics Group provideds detailed construction plans and schematics (Eagle)
• A Swiss high school STM project. Provides overview, processes and basic schematics (PDF).
• A low-cost (+/- $100) STM project. Good focus on the mechanical portions of the STM, but also with basic schematics (PDF).
• An amateur STM. Provides homebrew software.

Software

• Gwyddion is a modular program for SPM (scanning probe microscopy, of which STM is a subset) data visualization and analysis and is primarily intended for analysis of height fields obtained by means of SPM techniques (such as STM). FOSS/GPL.

• GXSM - the Gnome X Scanning Microscopy project. The GXSM software is a powerful graphical interface for any kind of 2D and up to 4D (timed and multilayered 2D mode) data acquisition methods, but especially designed for SPM. It includes methods for 2D data (of various types: byte, short, long, double) visualization and manipulation. FOSS/GPL

• SPIP - Scanning Probe Image Processor software package for nano- and microscale image processing. Supports multiple formats including STM instrumentation. Commercial/free trial.

Further Reading

• University of Erlangen technical STM theory.
• Slashdot thread on building your own STM.
• "Bryan's analytical instrumentation page" has a bunch of literature and web links related to STM.
• Wikibooks has a chapter on Scanning probe microscopy
• Wikipedia has a nice introduction to various forms of Wikipedia: Scanning probe microscopy such as Wikipedia: Scanning tunneling microscope, Wikipedia: Electrostatic force microscope, Wikipedia: Atomic nanoscope etc.
• the Wikimedia Commons has some STM-related images
• "If you buy a microscope for the home what level of detail would one be able to see?" gives these references for "building your own Scanning Tunneling Microscope (STM)":
  • 1. Lewis et al. "Student Scanning Tunneling Microscope" Am. J. Phys, 59(1), 38-42. (1991)
  • 2. Dieter W. Pohl, "Some design criteria in scanning tunneling microscopy", IBM J. Res. Dev., 30(4), 417-427, (1986)
  • 3. Binnig & Rohrer, "Scanning Tunneling Microscopy" IBM J. Res. Dev., 30(4), 355-369, (1986)
  • 4. Binnig & Smith, "Single-Tube Three-Dimensional Scanner for Scanning Tunneling Microscopy", Rev. Sci. Instrum. 57(8), 1688-1689, (1986)
  • 5. Sears et al., "A Scanning Tunneling Microscope for Undergraduate Laboratories", Computers in Physics Jul/Aug, 427-430, (1990)
• IBM research has published many articles about microscope design, including the above Pohl article.
• "How to build a Plastic-AFM head": The performance of this instrument has been investigated in a paper (Kühner 2007)
• Ferdinand Kühner, Robert A. Lugmaier, Steffen Mihatsch, and Hermann E. Gaub, "Print your atomic force microscope", Rev. Sci. Instrum. 78, 075105 (2007).
• Makezine: scanning tunneling microscope mentions
• Carbon Design Innovations sells carbon nanotube probes for atomic microscopes.