Site-selective silicon adatom desorption using femtosecond laser pulse pairs and scanning tunneling microscopy

We performed an experimental study of silicon adatom desorption from the Si(111)-7×7 surface using femtosecond laser pulse pair excitation with 80 fs pulse duration, 800 nm center wavelength, 300 mW average power, and a 100 MHz repetition rate. Using scanning tunneling microscopy, we directly recorded the desorption characteristics at each delay setting for each of the four adatom binding sites. The study revealed a preferential dependence between the delay time and the adatom sites within a 66.6–1000 fs delay range. © 2003 American Institute of Physics.