Gallium doped ZnS micro- and nanostructures: thermal synthesis and structural properties

Abstract

Ga doped wurtzite ZnS micro- and nanostructures have been grown by a catalyst free evaporation–solidification method. Different morphologies were obtained depending on the thermal treatment conditions and on the substrate, ZnS or alumina, used. The structures grown on ZnS are pyramids and diamond-like microcrystals, while the structures grown on alumina are plates from which pencil-like and triangular cross-section wires evolve as the Ga content increases. The structures have been characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD). It has been found that the main effects of gallium on the growth are the stabilization of polar {0001} or facets, not energetically favourable surfaces in pure ZnS, and the promotion of the auto-catalytic effect on positive (Zn2+ terminated) polar facets.