SEM & AFM

SEM & AFM: 

FORMULATE BY, APURV MODI(09EC09) AKASH PATEL(09EC02) SEM & AFM

Scanning Electron Microscopy (SEM): 

Scanning Electron Microscopy (SEM) The scanning electron microscope is a versatile instrument that can be used for many purposes and can be equipped with various accessories. The scanning electron microscope (SEM) uses a focused beam of high-energy electrons to generate a variety of signals at the surface of solid specimens .

Outline: 

Outline What can we use a SEM for? Components of the SEM

What can we study in a SEM? : 

What can we study in a SEM? Topography and morphology Chemistry Crystallography Orientation of grains In-situ experiments: Reactions with atmosphere Effects of temperature

Topography and morphology: 

Topography and morphology High depth of focus

Depth of focus: 

Depth of focus Optical microscopy vs SEM A SEM typically has orders of magnitude better depth of focus than a optical microscope making SEM suitable for studying rough surfaces The higher magnification, the lower depth of focus

Chemistry : 

Chemistry

In-situ imaging: 

In-situ imaging A modern SEM can be equipped with various accessories, e.g. a hot stage

Components of the instrument : 

Components of the instrument electron gun (filament) electromagnetic optics scan coils sample stage detectors vacuum system computer hardware and software (not trivial!!)

Applications : 

Applications The SEM is routinely used to generate high-resolution images of shapes of objects (SEI) and to show spatial variations in chemical compositions : acquiring elemental maps or spot chemical analyses using EDS Discriminations of phases based on mean atomic number using BSE . compositional maps based on differences in trace element "activators'" using CL. The SEM is also widely used to identify phases based on qualitative chemical analysis and/or crystalline structure . Precise measurement of very small features and objects down to 50 nm in size is also accomplished using the SEM .

Atomic Force Microscopy(AFM): 

Atomic Force Microscopy(AFM) Atomic force microscopy (AFM) or scanning force microscopy (SFM) is a very high-resolution type of scanning probe microscopy , with demonstrated resolution on the order of fractions of a nanometer , more than 1000 time. The AFM is one of the foremost tools for imaging, measuring, and manipulating matter at the nanoscale . s better than the optical diffraction limit .

How It Works: 

How It Works

The first atomic force microscope: 

T he first atomic force microscope

EXAMPLE OF AFM : 

EXAMPLE OF AFM The easyScan 2 scanning probe microscopes are ideal for a wide range of uses: teaching, research, and industry. East of use means short learning times and quick setup. Modularity means you can configure the systems to be as advanced or cost-effective as you need. Mobility means they are easy to transport - to the classroom, laboratory, job site, or production line.

Who Needs It: 

Who Needs It Vacuum, Air, Aqueous Medium - Mimic Biological Environment Sub-nanometer resolution Manipulate Surface with Molecular Precision Real Time Direct Structure-Function Studies 3-D Surface Topography Force Measurements in pico -Newton - nano -Newton range

Applications: 

Applications Study Unfolding Of Proteins Imagining Of Biomolecules Force Measurements In Real Solvent Environments Antibody-Antigen Binding Studies Ligand -Receptor Binding Studies Binding Forces Of Complimentary DNA StrandsStudy Surface Frictional Forces Ion Channel Localization

REFERENCE : 

REFERENCE WEBSITE: http://www.nanoscience.com www. wikipedia .org / www.mos.org BOOKS: 1)A Manual of Applied Techniques for Biological Electron Microscopy 2) Noncontact Atomic Force Microscopy