Semiconductor Cluster Surface Chemistry
Interim technical rept.
RICE UNIV HOUSTON TX DEPT OF CHEMISTRY
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The combination of laser-vaporization supersonic cluster beam techniques with the technology of fourier transform ion cyclotron resonance, FT- ICR, has opened a new approach to the detailed fundamental understanding of semiconductor surface chemistry. With this apparatus it is possible to trap clusters of a specific size in a superconducting magnet under ultrahigh vacuum conditions. Through collisions with an inert thermalizing gas it is possible to slowly cool the clusters down to room temperature, allowing them to anneal to the most stable possible form. In the case of silicon this technique has revealed that certain cluster sizes eg. 21,25,33,39,45 are particularly stable and unreactive with reagents such a ammonia and ethylene. These clusters are believed to have taken highly symmetric crystalline forms with the bonding patterns on the surface resembling those found on bulk single crystals. Such special clusters should serve well as microscopic testing grounds for detailed theoretical predictions of semiconductor surface chemistry.
- Physical Chemistry