Formation of ZnO nanocrystallites on ZnS surfaces by electron beam irradiation

Formation of ZnO nanocrystallites on cubic (3C) ZnS by electron beam irradiation has been investigated using a high-resolution analytical TEM. The specimen observed was a high-purity synthetic ZnS. In situ observations showed slight retreat of the synthetic ZnS surfaces and epitaxial formation of ZnO nanocrystallites, with orientation relationship of {111}Zns // {01.0}ZnO and <110>Zns//<10.0>ZnO. The ZnO nanocrystallites mostly adopt 2H structure, but 3C structure is also formed locally on ZnS, probably depending on the orientation and configuration of ZnS surfaces. It is proposed that these ZnO nanocrystallites are formed by electron-stimulated desorption (ESD) of sulfur from the ZnS surface and subsequent reaction of zinc and oxygen-containing gas from the vacuum in the microscope colunm.