Field Emission Scanning Electron Microscope is a type of microscope which uses electron beam as an illumination source instead of light (as in optical microscopes). FESEM is routinely used for imaging the surface topology of any material in the nanoscale regime (<100 nm). The electron beam is generated from suitable target materials such as Lanthanum hexaboride (LaB6) or Tungsten (W) by applying heat (thermionic emission) or high electric potential difference (Field emission). In case of FE-SEM, field emission is used that provides superior quality electron beam and thus better imaging as compared with conventional SEM.
When an accelerated beam of electrons (primary electrons) strikes the sample, secondary electrons are emitted from the sample due to energy absorption by the surface atoms of the sample. The angle and velocity of these secondary electrons is related to the surface topology of the sample. A secondary electron detector catches these escaping electrons and produces an electronic signal which is then amplified, transformed and processed into a video-image format. The surface topology of the sample can be viewed on a monitor and image can be saved for later use.
Only solid samples (Powder/Thin film) are admissible in FE-SEM equipment. Liquid samples (such as nanoparticle dispersion) are to be dried on suitable conducting substrates such as silicon wafer or copper wafer etc. before being analysed. It is also best to prepare powder samples by dispersing them in volatile solvents (methanol, ethanol, chloroform etc.) and drying it on conducting substrates.
FE-SEM imaging is carried on only conducting samples. For non-conducting samples (inorganic nanomaterials and thin films), a thin layer of gold is usually deposited over the sample. Gold coating of non-conducting samples is available on charge basis.
This FESEM (Field Emission Scanning Electron Microscopy) is used for CRYO SEM, and quantitative X-ray analysis and mapping
The FESEM equipment is utilized in imaging of materials which are submicron in size (< 1 µm). The equipment is routinely used for imaging of nanoparticles, surface morphology of thin films, coatings, polymer nanostructures etc.
It is also used for high resolution secondary electron (SE) and back-scattered electron (BSE) imaging at low and high kV, and cathode luminescence imaging.
Surface Profile Measurement Rs. 1400 per sample