Time-resolved STM studies of atom-movement effects on ionic–electronic conductor surfaces

The dynamics of photo-induced atom movements on an ionic–electronic conductor (Ag2Se) are discussed based on measurements of surface topology by scanning tunneling spectroscopy. All changing features of the surface topologies with various photo-exposure periods were successfully measured with a scanning tunneling microscope (STM). The surface shows a curved or flat mound inside the patterned-exposure region and a wall around the edge of the mound, which change with the exposure time. This indicates that the Ag-atom movement is dependent on the position inside the photo-exposed region and on exposure periods. So, the lateral diffusion constant of Ag movement is likely not to be a constant, but a function of position and exposure period.