Objectives

• Examination of the microstructure at high resolution
• Identification of phases
• Determination of the crystal structure and orientation of the phases
• Analysis of chemical composition of the individual phases.

People

Prof. Rahul Mitra

Facilitator

Metallurgical & Materials Engineering

rahul@metal.iitkgp.ac.in

+91-3222-283292

Equipment Details

High Resolution Transmission Electron Microscope

Utility and Working Principal

The high resolution transmission electron microscope is used to observe the structure and chemistry of electron-transparent crystalline or amorphous specimens, which could be metallic, ceramic, polymeric, or organic in character. The microscope records bright or dark field images, formed by the electron beam either transmitted or diffracted by the periodically arranged atoms, respectively inside a crystalline solid. The images and diffraction patterns contain information on the crystal structure and type of defects present in the solid. Lattice resolution images containing information on atomic-scale structure is obtained from thin crystalline specimens through interference between the diffracted and transmitted beams. Point-to-point resolution of 0.19 nm and line resolution of 0.14 nm are possible under controlled operating conditions. Chemical analysis is possible through detection of characteristic X-rays from different elements in the specimen using the attached Energy Dispersive Spectrometer. The HRTEM provides: (i) Bright and dark field images; (ii) selected area electron diffraction patterns; (iii) convergent beam electron diffraction; (iv) scanning transmission electron microscopy; (iv) Energy Dispersive Spectroscopy.