Morphology and Polarity of Double-plate ZnO Crystals from ZnF_2

Abstract

Plate-like ZnO crystals composed of two parallel component plates (double-plate crystals) were found in the growth of ZnO crystals from ZnF_2. Two component plates have a common c-axis and their outer surface is parallel to the basal plane. They are combined by a rod-like core crystal growing in the [2110] direction. In addition they have inverse polarity and are rotated by angles around the c-axis each other. The angle of rotation is in accord with the concept of coincidence-site lattice to some extent. Morphology and growth process of double-plate ZnO crystals are described.