In situ evaporation in a high-resolution TEM

Abstract

In recent years there has been a growing interest in the structure and stability of small particles at the atomic resolution level. In a number of cases, metal clusters were prepared ex situ and placed in a HREM which allowed significant contamination to be present. The one successful application to in situ work has been achieved by Takayanagi and his associates who have used a narrow gap pole piece 200 kV microscope modified to UHV conditions which achieves pressures in the 10-9Torr range. Studies with this microscope have shown small gold clusters of a few tens of atoms extending over edges of graphite surfaces and small clusters 20-30Å in lateral extent.