Scanning probe microscope are instruments that are utilized to analyze and study the surface properties of materials. The credit for inventing the first scanning probe microscope in the year 1981 goes to Gerd Binnig and Heinrich Rohrer of IBM laboratory who were recipients of the Nobel Prize in Physics for their invention. Soon, a variety of scanning probe microscopes were developed. They differed in the nature of the probe and the way it interacted with the surface. Scientists can use these instruments to image and typify materials at atomic levels. These microscopes have helped scientists make several ground breaking nanotechnology achievements that would not have been possible otherwise.
Basic Components Of Scanning Probe Microscope
The probe and the scanner are the basic components of the SPM. The probe is designed to sense and analyze the interaction that occurs at atomic levels when two surfaces are brought together. A piezoelectric scanner is used in SPM that can be made to bend, contract or even expand in a precise and calculated manner. This is used in maintaining probe-sample distance and in controlling the movement of the probe on the surface of the material. A set point is established and scanning begins when the detector signal and the set points are the same. The probe is moved over the surface in a raster pattern and when it senses a reaction it produces a detector signal. As the topography changes variations occur in the detector signal. The difference between the set point and the detector signal is referred to as the error signal. When these error signals are plotted point by point, the SPM image is generated.
Scanning Probe Techniques:
STM Or Scanning Tunneling Microscopy
The Scanning Tunneling Microscope was the first SPM that was invented in 1981. Such an instrument is also used in scanning tunneling spectroscopy techniques. In this technique the topography of a surface is studied using a tunneling current. The tunneling current is dependent on the distance between the probe tip and the surface. This technique is used to study conductive and semi-conductive surfaces, polypeptides, mono-layers, biological materials and polymers. It is also used to study the structure and behavior of metallic surfaces.
Atomic Force Microscopy
In this technique the tip of the probe is located in a cantilever which bends or deflects when it is brought near the surface. The deflections are measured when the tip scans the surface and a computer creates an image. They are used to study conductive, semi-conductive, biological surfaces and insulators. There are four basic AFM modes. They are the contact, non-contact, tapping and torsional resonance modes. An atomic force microscope is also known as the scanning force microscope. It was invented in 1986 by Binnig, Quate and Gerber. This instrument is also used in force spectroscopy techniques.
Near-field Scanning Optical Microscopy
In this technique the tip-surface is measured by a probe controlled by a piezoelectric scanner. This is done by passing light through an optical fiber which excites the surface. This technique makes it possible to get images with resolutions beyond the Abbé diffraction limit.
Scanning probe microscopes can also be used to alter, manipulate or modify the surface. Some of the techniques they are used in them are Nanolithography, Nanoscratching, Nanomanipulation and Nanoindentation. Obtaining a scanning probe microscope is not a hard task as many firms offer customers a wide selection of models to choose from. Be sure to compare rates and features of the instruments before you place an order.
