Fault Structures in Wurtzite

A more precise interpretation of the defect structure of wurtzite crystals as observed in the electron microscope is presented. It was found previously that the crystals contain faults in the basal planes (b‐faults) and in prism planes (p‐faults). Direct evidence is presented indicating that the transition wurtzite sphalerite is a martensitic transformation due to the movement of partial dislocations. The transformation leads to a faulted structure. Evidence is further presented for the occurrence of a domain structure. Possible models for this domain structure are proposed. According to the first, the domain boundaries result from the contact between two crystal regions for which the polar c‐axes have opposite sense. The origin of the contrast at such boundaries is discussed, and it is concluded that this type of boundary has presumably not yet been observed in wurtzite. According to the second model the boundaries result from the contact between two crystal regions which are displaced with respect to each other over a displacement vector which is identical to the Burgers vectors of a partial in the basal plane, or to the sum of such a vector with a vector (000 c/2) Evidence is presented to show that the domain structure results from the introduction during growth of single stacking faults. A generation mechanism for basal and prismatic faults is discussed. The contrast effects at single and double faults in the hexagonal closed packed structure are discussed in detail and a method is proposed to distinguish these two types of faults.