DIEEM DIelectric coating for Electron EMmission
Abstract
Advances in materials science offer a wide range of options for exploring new physical properties, particularly in extreme regimes. Among these, strong field regime is a prime research area. Above a critical electric field, any solid surface emits electrons by tunneling, a wave mechanics phenomenon. Electron emission can be seen as a natural tool for understanding the basic phenomena involved and-or as a by-product of the (light, matter) interaction to be either maximized (electron cathode sources) or minimized (breakdown in radiofrequency cavities). The main objective of the proposed research is to answer fundamental questions related to the electron emission by a material surface under strong electric field regime. These questions will be addressed by a surface analysis technique well suited to the subject, whose imaging principle is based directly on the collection of the emitted electrons, whatever the physical process involved (thermal, photoemission, cold field emission). This electron cathode microscopy is the electron photoemission microscopy PEEM. PEEM microscopy offers a multidimensional approach in (space, energy, time). It provides a spatial image of emitted electrons with sub-wavelength resolution. It can therefore help uncover spatial variation in field emission yield at the mesoscopic scale. PEEM is an energy-sensitive technique. It will provide electron energy distribution curves, a footprint of the mechanisms at play. PEEM relies on pulsed laser sources, it can determine the dynamics of the electron emission on a short time scale. All these diagnoses will contribute to our understanding of the electron emission characteristics of new materials and provide feedback for their growth and modeling. The materials envisaged exploit the singular properties of carbon nanotubes and-or take advantage of plasmonic phenomena in confined environments such as those encountered in metal-insulator-metal MIM-type structures. The influence of dielectric coatings on emission physics will be studied from the point of view of field confinement and-or improving the mechanical strength of emitters. As a natural extension of the proposed research theme, the physics of optical breakdown in dielectric media will be addressed. This latter aspect represents a major challenge for electronic probes, due to the possible occurrence of charging effects detrimental to instrument operation.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 22, 2024
- Source ID
- FA86552317073
Entities
People
- Ludovic Douillard
Organizations
- Air Force Office of Scientific Research
- United States Air Force