TIME-RESOLVED PHOTOELECTRON-SPECTROSCOPY OF GERMANIUM AND SILICON DURING THE SOLID TO THE LIQUID-STATE PHASE-TRANSITION

Photoelectron spectroscopy of liquid silicon and germanium has been pe rformed by using a new technique based on laser-pulse induced melting of sample surfaces and time resolved detection of the photoelectrons. With this method it has, for the first time, been possible to observe the solid to liquid phase transition of silicon, an element with a vap or pressure in the liquid phase which is orders of magnitude higher th an the acceptable value in standard photoemission. Due to the identica l experimental conditions during the characterization of the solid and liquid state, a direct comparison of photoelectron spectra can be mad e qualitatively as well as quantitatively, This is shown in the two ca ses of silicon and germanium.