Laser pulse desorption under scanning tunneling microscope tip-Cl removal from single site on Si(100)

Abstract

The desorption of pairs of chlorine atoms influenced by the tip of a scanning tunneling microscope is achieved at preselected sites on the Cl-saturated Si(100)-(2×1) surface using nanosecond laser pulse irradiation of the tip within the tunneling range. Bright features observed for the empty state topographic images after a laser pulse sequence are interpreted to be due to bare Si–Si dimers formed by laser induced desorption of two Cl atoms underneath the tip. The Cl desorption mechanism involves the enhancement of the sample-tip interaction due to laser pulse induced tip heating and tip expansion.