Exploring the direction of dislocation line in pyramid section of KDP crystal using 3D confocal microscope

By the process of etching and polishing, the dislocation-related etch pits were clearly created on the pyramidal faces for as-grown KDP crystals by rapid growth technique. Through a combination of 3D confocal microscope and optical microscope, the direction of dislocation lines were studied in pyramid section, and the corresponding morphologies of etch pits were also observed in detail. The results show that the dislocation lines are mainly located in the {0 1 0} faces, and the dislocation-related etch pits may be caused by screw dislocations. Moreover, the research indicates that the morphologies of dislocation-related etch pits are somewhat related to the direction of dislocation lines. For the inclined sectors of Iʹ and IIʹ on etch pits, the slope ratio of Iʹ/IIʹ decreases with the increases of β as an angle between the direction of dislocation line and the normal of {101} face. Therefore, the information of dislocation in crystal, especially the orientation of dislocation line, can be inferred by the spatial size characteristics of dislocation-related etch pits.