Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5364694 | Applied Surface Science | 2007 | 4 Pages |
The mechanisms of laser ablation of CdS targets at different laser wavelengths have been investigated. (CdS)n+ cluster formation is only observed upon 532Â nm ablation. The time and energy distributions of neutral S, S2, Cd and CdS show significant dependence on laser wavelength. Bimodal distributions are observed at 266 and 308Â nm. For the former, the average kinetic energy increases significantly with mass, taking values in the range of 0.3-1.7Â eV. At 308Â nm the slow component of the time distribution disappears at distances above the target larger than 1Â cm. At this wavelength, the observed time distribution appears to reflect mainly the dynamics of the expansion. At 532Â nm the time distribution is monomodal and the average kinetic energies are below 0.2Â eV. Clear indications of the participation of thermal (at 532Â nm) and non-thermal mechanisms (at 266Â nm) have been found. It is tentatively concluded that the cluster formation observed upon ablation at 532Â nm can be related to the thermal ablation mechanisms in which the low kinetic energy of the species in the plume and their similar velocities favor the aggregation processes.