Near-Ultraviolet Laser Photoemission: Scanning Microscopy, Buried Interfaces and Image-Potential States.

This work reports the use of near-ultraviolet laser radiation, through the photoelectric effect, in the development of probes for surfaces. This effect offers the advantage of being contactless and non-destructive, even at photon fluences at which non-linear effects, such as two-photon photoemission processes, are observed. The probing of the energy band parameters at insulator/semiconductor buried interfaces is demonstrated. A study of the sensitivity of image-potential induced states upon temperature changes and atomic adsorption is presented, which leads to the uncovering of a new method to measure the temperature dependence of work functions on most metallic surfaces. Finally, a new, simple, photoemission scanning microscope is developed, which circumvents the need for energy-resolved techniques, for the mapping of doped regions on semiconductor surfaces.