Argon ion sputtering

The Au(lll) crystal was cleaned using the procedure of ref. (12) by heating in 2x1torr of NO2 at 800 K to remove carbon from the surface. Cycles of cleaning in NO2 followed by argon ion sputtering at 800 K were repeated until no "oxide" was formed by NO2 exposure and no carbon was detected. The crystal was then annealed to 800 K and gave the expected LEED pattern for the reconstructed surface. 

The preparation of clean surfaces in uhv has become by now a standard procedure. Several texts deal with this problem [see for example Refs. (21) and (22)]. Single crystal surfaces are generally cleaned by chemical means (e.g. oxidation and subsequent flashing in the case of tungsten) or by argon ion sputtering (23) or by a combination of both (24). 

Smardzewski et reported SERS studies of pyridine adsorbed on a polycrystalline silver sample treated by argon ion sputtering at 77 K. Prior to introduction to the UHV system, the silver substrate was polished using the mechanical treatment described above. Zwemer et have used iodine vapor illuminated... 

Figure 3. Hardness of ncNiCr (80/20 weight-%) alloy prepared by argon ion sputtering against crystallite size (from [51] with permission).

Relative Atomic Concentration Ratio of Cr to C as a Function of Argon Ion Sputtering Time. 

Another similar pretreatment involves argon-ion sputtering for 45 min at 750 eV in the UHV using an argon gas pressure of 10 Torr (140). These conditions were selected to remove the adventitious carbon and surface hydroxides but not to cause extensive oxide reduction or lattice damage. Before either of these treatments, the samples should first be solvent cleaned as desalbed above. 

---