Reaction studies of gallium arsenide clusters: Models of real surfaces
Chibante, Luis Paulo Felipe
Master of Arts
As semiconductor technology continues to miniaturize, surface phenomenon become prevalent. Clusters can be considered as model compounds of the surface in free space. By performing experiments on clusters, it is equivalent to focussing on local sites of the bulk surface, and building it one atom at a time. The development of supersonic beams of clusters has proved to be one of the most powerful methods in preparing the "nano" state, the intermediate range between atomic and the macroscopic description of matter. Fourier Transform - Ion Cylcotron Resonance (FT-ICR), a mass spectrometry technique, coupled with these cluster beams was used to study gallium arsenide, a well-utilized semiconductor. The complexity of isomers and the stoichiometric distribution within a given cluster size has been simplified using mathematical methods for signal deconvolution. By studying reaction parameters with ammonia, gallium arsenide clusters proved to be an adequate comparative model for real surfaces. Furthermore, local density theoretical calculations, which are feasible on these small clusters, provided a corroborative and predictive proving ground for this system.