Scanning probe microscopy SPM

Analogous to record players, a SPM tip is supported by a flexible cantilever. During analysis, the tip is slowly rastered across the surface of a material - either a few Angstroms away from the surface (noncontact mode), or in contact with the sample (contact mode). There are two primary forms of 

Noncontact AFM overcomes the frictional and adhesive forces between the tip and sample by hovering the tip a few Angstroms above the surface. In this mode, the attractive van der Waal forces between the tip and surface are monitored. As you might expect, these attractive forces are much weaker than those generated in 

Without question, AFM exhibits a much greater versatility for surface analysis than STM. In particular, the following variations are possible, through altering the nature of the tip  

Scanning probe microscopy (SPM) is the general name for the use of any of a variety of microscopes that have one basic feature in common. The common feature is that the image is produced by scanning a solid probe on or just above the surface of a specimen, and detecting 

The active part of an SPM, that is the probe, its piezoelectric drivers and mounting are rather small, a few inches across in all. Thus one solution to the difficulty of locating a particular area to be viewed at high resolution is to place the whole microscope in the specimen chamber 

Some of these SPM systems can be combined with others - a conducting tip on a cantilever can be operated as a combined STM and AFM. Measurement of both vertical and lateral forces gives a FFM and AFM. Tunneling from a thermocouple tip gives STM and STP, and the combined effect measures local chemical potential [86]. 

Both the STM and the AFM have been used for nano-fabrication, deliberately moving atoms around on the surface of the sample. This shows that large local forces can be generated in the 

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Since the introduction of scanning tunnelling microscopy, a family of scanning probe microscopies (SPMs) have been developed (Table 3.1), with three main branches resulting from three different types of probe. All of the methods have in common the ability to image surfaces in real space at nanometre or better resolution, are straightforward to implement and are relatively low in cost. 

The already critical need for molecular-scale compositional mapping will increase as more complex structures are assembled. Currently, electron microscopy, scanning probe microscopy (SPM) and fluorescence resonance energy transfer (FRET) are the only methods that routinely provide nanometer resolution. 

See also SEM/EDS detectors used in, 24 78 development of, 16 487-488 electron sources used in, 24 77-78 in surface imaging, 24 75-76 silica, 22 371-372 for trace evidence, 12 100 Scanning probe microscopies, in surface and interface analysis, 24 80-84 Scanning probe microscopy (SPM), 16 466, 495-503... 

Scanned probe microscopies (SPM) that are capable of measuring either current or electrical potential are promising for in situ characterization of nanoscale energy storage cells. Mass transfer, electrical conductivity, and the electrochemical activity of anode and cathode materials can be directly quantified by these techniques. Two examples of this class of SPM are scanning electrochemical microscopy (SECM) and current-sensing atomic force microscopy (CAFM), both of which are commercially available. 

For direct patterning on the nanometer scale, scanning probe microscopy (SPM) based techniques such as dip-pen-nanolithography (DPN), [112-114] nanograftingf, nanoshaving or scanning tunneling microscopy (STM) based techniques such as electron induced diffusion or evaporation have recently been developed (Fig. 9.14) [115, 116]. The SPM based methods, allows the deposition of as-sembhes into restricted areas with 15 nm linewidths and 5 nm spatial resolution. Current capabihties and future applications of DPN are discussed in Ref. [117]. 

Among the many microscopy-based techniques for the study of biomolecules immobilised on surfaces, scanning probe microscopies (SPM) and especially atomic force microscopies (AFM) are arguably the most used techniques because of their molecular and sub-molecular level resolution and in situ imaging capability. Moreover, the invasiveness of AFM, which is less of a problem for the DNA molecules, is essential for another two functions, apart from the mapping of surface nanotopographies, namely the quantification and visualisation of the distribution of chemistry, hydrophobicity and local mechanical properties on surfaces and the fabrication of nanostructures. 

Around 1980 a new method of microscopy known as scanning probe microscopy (SPM) was invented. Within the past ten years, applications have been increasing exponentially in fields like surface physics and chemistry, biology and optics. SPM is also beginning to emerge as a usefvil and popular technique for R D and quality control in several industries. 

There are numerous modern developments that have made atomic-scale resolution possible in recent years. In fact, some of these developments in instruments can also be used to measure forces between particles and surfaces. These developments for force measurements are discussed briefly in Section 1.6c and in Vignette 1.8. In this section, we review electron and scanning probe microscopies (SPMs), which allow atomic-scale visualization of surfaces and particles. 

Various surface analytical tools have been utilized to investigate the surface and bulk properties of the SAMs, such as X-ray photoelectron spectroscopy (XPS),22 Fourier transform infrared spectroscopy (FTIR),23 Raman spectroscopy,24 scanning probe microscopy (SPM),25 etc. 

Near-Field Scanning Optical Microscopy (NSOM) is a technique which enables users to work with standard optical tools integrated with scanning probe microscopy (SPM). The integration of SPM and certain optical methods allows for the collection of optical information at resolutions well beyond the diffraction limit. 

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