School of Physics and Astronomy Colloquium

Speaker:  Rudolf M. Tromp, IBM T.J. Watson 
Subject: Low Energy Electron Microscopy

In Low Energy Electron Microscopy (LEEM) and Photo Electron Emission Microscopy (PEEM) the sample forms the cathode in a strongly decelerating/accelerating immersion objective lens. This enables low energy electrons at the sample (0-100 eV) to be used for high resolution (2 nm) image formation, diffraction, and spectroscopy. This form of microscopy came to fruition in the early 1990’s, much later than other forms of electron microscopy, and has undergone a rapid development since.

In this talk I will discuss some of the principles and unique capabilities of cathode lens microscopy (as it is generally known), and illustrate its wide range of applications with recent examples from our research program, including growth and properties of 2D materials, occupied and unoccupied momentum-resolved electronic structure, reflection/transmission experiments to study electron mean free path, and the effects of low energy electron irradiation on thin resist films. A unique feature of many of these experiments is that the lab is inside the electron microscope, rather than the other way around.I