Bulk growth of ZnGeP2 crystals and their study by X-ray topography

摘要: Abstract Structural defects were studied in the nonlinear optical material ZnGeP 2 (ZGP) grown by vertical Bridgman technique from melt. Progress ZGP growth with sufficiently perfect structure allowed us observe Borrmann effect and to apply X-ray transmission topography method based on this for first time ZGP. Types of defined comparison experimental simulated topographs. In as-grown crystals found striation, various dislocations, coherent semi-coherent particles second phases, inclusions, initial part crystal compositions lying along ZGP–GeP pseudobinary cut. Inclusions forming solute trails end ingots ZGP–ZnP The dislocation density changed N d ~3.5×10 3  cm −2 ~2.5×10 onset ingot, respectively. FWHM rocking curves ranger 13″ 35″. A high absorption coefficient 0.65–2.5 µm spectral region, always existing ZGP, can be reduced thermal annealing electron irradiation down ~0.02 cm −1 at 2.06 µm.