DYNAMIC OBSERVATION OF AG DESORPTION PROCESS ON SI(111) SURFACE BY HIGH-TEMPERATURE SCANNING-TUNNELING-MICROSCOPY

The dynamical isothermal desorption process of Ag adsorbed on a Si(111) surface kept at about 600-degrees-C was observed by means of high-temperature scanning tunneling microscopy (HT-STM). The desorption of Ag caused a transition from the square-root 3 x square-root 3-Ag phase to the 3 x 1-Ag phase having a lower Ag coverage, followed by another transition to the 7 X 7 phase. In the respective phase transitions, the produced phases extended from steps and domain boundaries. The number of Si atoms moved is discussed for the case of the phase transition from the 3 x 1-Ag structure to the 7 x 7 structure.