Unit for Nanocharacterization  Equipment and Techniques SPM
Scanning Probe Microscope - Nanoscope Dimension 3100 SPM - Overview SPM - Basics and Tutorials SPM - Specifications
Basics and TutorialsIn the early 1980s, scanning probe microscopes (SPMs) dazzled the world with the first real-space atomic-scale images of surfaces. Now, SPMs are used in a wide variety of disciplines, including fundamental surface science, routine surface roughness analysis, and spectacular three-dimensional imaging - from atoms of silicon to micron-sized protrusions on the surface of a living cell. The scanning probe microscope is an imaging tool with a vast dynamic range, spanning the realms of optical and electron microscopes. It is also a profiler with unprecedented resolution. In some cases, scanning probe microscopes can measure physical properties such as surface conductivity, static charge distribution, localized friction, magnetic fields, and elastic modulus. Hence, SPM applications are very diverse. Scanning probe microscopes are a family of instruments used for studying surface properties of materials from the micron all the way down to the atomic level. Two fundamental components that make scanning probe microscopy possible are the probe and the scanner. Atomic Force Microscopy (AFM) The atomic force microscope (AFM) grew out of the scanning tunneling microscopy (STM) and today it is by far the more prevalent of the two. Unlike STMs, AFMs can be used to study insulators, as well as semiconductors and conductors. The probe used in an AFM is a sharp tip, typically less than 5micrometer tall and often less than 10nm in diameter at the apex. The tip is located at the free end of a cantilever that is usually 100-500 micrometer long. Forces between the tip and the sample surface cause the cantilever to bend, or deflect. A detector measures the cantilever deflections as the tip is scanned over the sample, or the sample is scanned under the tip. The measured cantilever deflections allow a computer to generate a map of surface topography. Several forces typically contribute to the deflection of an AFM cantilever. To a large extent, the distance regime (i.e., the tip-sample spacing) determines the type of force that will be sensed. Variations on this basic scheme are used to measure topography as well as other surface features. There are numerous AFM modes. Each is defined primarily in terms of the type of force being measured and how it is measured. For basic education and principle understanding of the SPM, we kindly ask you to use following web resources:
|
