Study of structural defects in ZnGeP2 crystals by X-ray topography based on the Borrmann effect

The first study of structural defects in a ZnGeP2 semiconducting nonlinear optical crystal has been carried out by X-ray topography, based on the Borrmann effect, and the effect of anomalous transmission of X-rays on ZnGeP2 crystals has been examined. It is shown that the rosette technique of defect study under conditions of the Borrmann effect, developed earlier for elementary semiconductors, can be applied to the study and identification of defects in ZnGeP2. Features of contrast from individual edge and screw dislocations, microdefects, and coherent and semi-coherent microinclusions were considered. Defect identification was carried out by comparison of the experimental intensity contrast with simulated images of the defects.