Surface analysis of many materials can be impeded by the presence of contaminant substances at the surface. Signals from these contaminants can dominate a photoelectron spectrum, leaving little contribution from the underlying material of interest. Spectroscopic analysis of contaminated samples can be a considerable challenge in surface science, so methods of cleaning samples are of some importance. One common method of removing contamination in vacuo is argon ion sputtering, which can be effective at removing surface materials. Damage to the underlying material can be substantial with argon ions, however, particularly at high impact energies. Ion impacts can disrupt polymer structures and reduce inorganic oxides, so that the surface after cleaning does not closely resemble the intact material.

 

The recent development of argon cluster ion beam sources promises significant improvements in depth profiling of soft materials. Cluster beams can offer exceptionally gentle sputtering, and so may be ideally suited to removal of contaminants and surface modifications from a variety of samples.

 

In this presentation, we evaluate the utility of argon cluster ions for the surface cleaning of various materials, in combination with the Thermo Scientific ESCALAB250Xi surface analysis instrument for characterisation of the samples. The results of gas cluster profiling on polymeric and inorganic materials will be presented, with spectroscopic and imaging analyses showing the benefits of this method.