Abstract

The desorption of molecular species on metal surfaces by pulsed laser radiation is examined for the first time with secondary ion mass spectroscopy (SIMS). SIMS has a surface sensitivity of <10^-4 monolayer^1,2 due to the moderately efficient production of charged secondary ions coupled with the high ion collection efficiency and high detector gain of quadrupole mass spectrometers. When a very low primary ion current is used (<50 nA), the presence of specific molecular adsorbed species such as hydrocarbons and water can be continually monitored without significantly changing surface composition.³ This static form of SIMS can thus reveal laser-induced changes in the surface com- position. When the dynamics of laser-induced surface processes are of interest, time-resolved SIMS can be performed by rapidly sweeping a quadrupole mass filter before and after the laser is triggered.

© 1983 Optical Society of America