Field emission as a tool for material characterization in the tunneling regime

Vacuum electron sources have a long history dating back to the end of the nineteenth century, and have been at the root for many revolutionary developments, such as the advent of telecommunications and the computer. Today, these sources are indispensable for electron microscopy and X-ray generation. This presentation will focus on the most quantum of these sources, namely field emission sources, which provide electron beams with the highest brilliance and coherence. The physical phenomenon at the heart of field emission is the tunnel effect. This phenomenon was theorized almost 100 years ago, first in chemistry by Friedrich Hund, then by Oppenheimer for the ionization of atoms, Fowler and Nordheim for field emission, and finally Gurney, Condon, and Gamow for the alpha decay, all within the space of a year. None of them received the Nobel Prize for the microscopic tunnel effect.  

I will take the opportunity of this year's Nobel prize in physics attributed to the discovery of macroscopic quantum mechanical tunneling to revisit microscopic tunneling. I will review the historical equations of the field and show why field emission has been so far unable to give accurate measurements of the work function of materials. I will also illustrate how field emission can be used to study femtosecond tunneling phenomena and characterize the electronic, thermal and mechanical properties of nano-objects.