A Bridgman growth furnace was modified by adding adiabatic material between two furnace tubes. The appropriate temperature gradient of 10～30 ℃/cm at the growth interface was obtained by adjusting the distance between the two sections and controlling their temperature. The infrared nonlinear optical (NLO) crystal LiInS2 was successfully grown by the accelerated crucible rotation technique (ACRT). The crystal was characterized by using XRD and transmission microscopy. It is found that the UV-VIS-NIR and Mid-IR transmittances are about 40%.
Potassium tantalate niobate (KTa1-xNbxO3, KTN) crystals with different dimensions and quality situations were grown by Czochralski method. Crystal growth process and morphology properties of KTN are presented in this paper. It was found that some defects, such as bubble, inclusion, crack, dislocation etc., can all appear if the crystal is grown in an improper condition. The character and formation mechanism of such defects in macro growth are discussed. We consider that the CO2, which was not released absolutely during the sintering process and dissolved in the melt, led to bubbles. The composition of the inclusion caused by high pulling and rotation rates is KTN polycrystalline. The crack and dislocation in KTN crystal mainly come from improper temperature field. Etching and high-resolution X-ray diffraction (HRXRD) experiment results indicate that the central area is the defects concentrated. PACS: 81.10.
