Reactive Etching of Ga sub x As sup - sub y By HCl

The size-dependent reactivities of silicon clusters have provided insights into the cluster sites responsible for reaction. Gallium arsenide clusters provide an additional dimension to be examined; the stoichiometry of the cluster. The variation from gallium-rich to arsenic-rich clusters have been observed to increase the electron affinity of these clusters. In the present study, the reactions of Ga sub x As sup - sub y with HCl have been examined. The reactions primarily involve etching of the bare clusters through loss of GaCl; a minor pathway involves proton transfer for HCl to produce Cl sup -. The reaction rates show a dramatic dependence on stoichiometry with variations of one to two orders of magnitude measured for a given cluster size. At least two cluster stoichiometries, Ga sub 2 As sup - sub 3 and Ga sub 2 As sup - sub 4, have dual populations that can be differentiated kinetically. The dual populations are ascribed to geometric isomers.