THE STRUCTURE OF SMALL GAAS CLUSTERS

Communication: Semiconductor clusters, particularly gallium arsenide, have potential applications in nonlinear optical devices. Special inte rest is generated by the fact that their optical and electronic behavi or depends on the size of the cluster. Direct evidence is presented fo r the occurrence of hexagonal, i.e., wurtzite-type structure, GaAs in clusters, whereas bulk GaAs has zincblende structure. High-resolution transmission electron microscopy, atomic force microscopy and electron diffraction results are reported and interpreted. Suggestions are mad e for further work.