The analysis of defects by observation of moiré fringes from overlapping crystals—application to zinc sulphide crystals

Abstract The closure failure b of a Burgers circuit in the distorted lattice is shown to be related to the closure failure αd/2π of the corresponding circuit in moiré fringes by the relation a = 272πg. b where g is the index of the plane in the Bragg condition in the faulted crystal and d is the spacing of the moiré fringes. This correspondence is applied to the determination of the fault vectors of stacking faults and partial dislocations in wurtzite zinc sulphide crystals. The stacking faults on (0001) have fault vectors of the type 1/22023. Stacking faults on the prismatic planes 1120 have fault vectors of the type 1/21011 or 1/21123. These two fault vectors are indistinguishable by this method. The partial dislocations terminating stacking faults on (0001) are found to have 1/20223 as fault vector.