Atomic Force Microscopy (AFM)-KMBB
Description
An Atomic Force Microscope (AFM) is a type of microscope that belongs to a family of microscopes known as Scanning Probe Microscopes (SPMs). Such microscopes use a physical probe tip, mounted on a cantilever, that is scanned back and forth, in a raster pattern, over the sample surface. In a way, this method can be likened to a blind man who uses a stick to “see” the terrain on which he is on. The deflection of the AFM cantilever as the probe tip moves over the sample surface is tracked by a laser beam that is reflected at the back side of the AFM cantilever. A position sensitive photodetector detects the deflection of the laser and such information is used in the feedback loop to create a 3D topographic image after the scanning process. An AFM is an SPM that makes use of the electrostatic forces between the cantilever tip and the sample to generate an image. A magnetic force microscope (MFM) is an SPM makes use of magnetic forces, while a scanning tunneling microscope (STM) is an SPM that uses the electrical current flowing between the sample and the cantilever tip. The AFM was developed to overcome the challenges faced by its predecessor, the STM. Unlike the STM, which can only image conducting or semiconducting samples, an AFM can image conducting and semiconducting materials, as well as polymers, ceramics, composites, and biological samples. Depending on the information that is needed, the AFM can be operated in two basic modes of imaging. The first one is called the Static or Contact Mode. The second mode is known as the Dynamic Mode under which we have the Tapping (intermittent contact mode) and the Non-Contact Mode. In this activity, we are going to visualize and analyze AFM data using Gwyddion, a free and Open-Source software for visualizing and analyzing data obtained using Scanning Probe Microscopy techniques, like AFM. The said software can be used for general height field and image processing. Gwyddion can be downloaded from http://gwyddion.net/download.php. Image processing of AFM data are of two kinds: First, are those processes that compensate for instrument defects or to remove artifacts, and the second, are processes that quantify surface information.