ELECTRON MICROSCOPY: AN INTRODUCTION TO SEM AND TEM

Electron microscopes are essential analytical tools in the field of materials science. Aim of the course is to give a broad view of the topic, putting it in the general frame of Optics, and introducing step-by-step the specific characteristics of electron instruments, which are due to the different kind of interactions of electrons with matter. The goal is to allow the student to use electron microscopes with awareness.

The student will be able to correctly interpret electron microscopy images that he will find in the scientific literature. He/she will have awareness of the different techniques to be used in relation to the samples to be examined. The student will be able to understand the features of the different signals used in scanning (SEM) and transmission (TEM) electron microscopy and the influence that the different operational parameters may have on the images.

Only basic knowledge of the physics of waves and of electromagnetism are requested.

Visible light and electron features: a comparison.
Geometrical optics.
Inter-relationships between diffraction limit, aberrations, resolution and depth of field.
Abbe’s theory.
Conjugated planes and apertures’ functions.
Light and electron microscopes (transmission, reflection, scanning).
Aberrations.
Electron-matter interaction and contrast mechanisms.
Spectroscopy in the electron microscope (EDS, EELS).
Demonstration of the use of SEM and TEM, possibly on samples produced by the students for the research work.

J. Goldstein et al., Scanning Electron Microscopy and Microanalysis, Springer Verlag, 2003
D.B. Williams and C.B. Carter, "Transmission Electron Microscopy, A text for materials scientists", Springer Verlag, 2009

The progress in learning will be checked through the discussion of scientific papers, which make use of electron microscopy, in the research field of the student.

The theory is described in the class with the aid of a Power Point presentation which is given to the students at the end of the course.
Almost half of the course is dedicated to practical demonstration divided in two parts:
1)SEM: demonstration of the difference between secondary and backscattered electrons and of the influence of the different operative parameter on the obtained images; EDX microanalysis.
2) TEM: demonstration of bright field on nanoparticles and effect of the objective aperture on the image; high resolution (HRTEM); Fourier Transform of a HRTEM image and use of a mask for the anti-transform, as an aid to understand the Abbe theory of image formation: electron diffraction; EDX microanalysis. Investigation of the samples brought by the students.

English

Accessibility, Disability and Inclusion

Accommodation and support services for students with disabilities and students with specific learning impairments:
Ca’ Foscari abides by Italian Law (Law 17/1999; Law 170/2010) regarding supportservices and accommodation available to students with disabilities. This includes students with mobility, visual, hearing and other disabilities (Law 17/1999), and specific learning impairments (Law 170/2010). In the case of disability or impairment that requires accommodations (i.e., alternate testing, readers, note takers or interpreters) please contact the Disability and Accessibility Offices in Student Services: disabilita@unive.it.

oral