Investigation of crystal growth of 50 mm CZT using SiC pedestal and pBN crucible

Large Size Crystal Growth, Photoluminescence, Crystal Excellence, and Hardness Properties of In-Doped Cadmium Zinc Telluride

“…Growth feedstock consisted of 170 g of feedstock CdZnTe, 5% Zn, along with 0.6 mg In, corresponding to a concentration of 1.15 e +17 at/cm 3 and loaded in PBN crucible which was further inserted in quartz ampule and then sealed at high vacuum. The well-sealed ampule was placed on top of a quartz ampule with a SiC “coldfinger” in the center of vertical gradient freezing furnace. , The coldfinger increased heat extraction from the bottom of the ingot, ensuring a more controlled nucleation event and an initially convex solid/melt interface. The monitoring of temperature was done through five thermocouples which were applied along outside of ampule at different heights: 0.0, 2.2, 4.2, 5.4, and 8.1.…”

“…The initial bell-shaped temperature profile helped to maintain the convex melt interface, and also resulted in intense fluid convection, improving isolation of surplus Te in melt and thus tumbling the formation of Te inclusions in solid . The melt-back, SiC coldfinger and bell-shaped temperature profile helped to ensure favorable solidification conditions at the critical beginning stages of the growth, which largely determine the crystal quality throughout the entire ingot. − The shift toward a “Straight” temperature profile is necessary to ensure that the top third of the ingot solidifies in a controlled manner, at the target value of 0.5 to 1 mm/h. The growth procedure is described in greater detail and verified by experimental and numerical simulation results in our previous publication .…”

“…The well-sealed ampule was placed on top of a quartz ampule with a SiC "coldfinger" in the center of vertical gradient freezing furnace. 18,19 The coldfinger increased heat extraction from the bottom of the ingot, ensuring a more controlled nucleation event and an initially convex solid/melt interface. The monitoring of temperature was done through five thermocouples which were applied along outside of ampule at different heights: 0.0, 2.2, 4.2, 5.4, and 8.1.…”

“…In earlier eras, various kinds of research and development have been done on CdZnTe (CZT) and its related compounds to achieve a good quality RT X-ray and γ-ray detector-grade single crystals that also can be applied in key applications. − The single crystals of CZT have been grown by different techniques, such as high-pressure vertical Bridgman, modified vertical Bridgman (MVB) technique, traveling heater method, , electrodynamic gradient freeze (EDG) furnace, vapor growth, and oscillatory Bridgman technique. , The analysis on grown CZT crystal shows that the crystals possess grain boundaries and other imperfections like: great Te inclusions, twin, and dislocations that makes limited use of CZT. ,− Among all these technique vertical gradient freezing (VGF) − is found to have better results in terms of good quality with less defects crystals for detection applications. The single crystals of CZT with different dopants such as, Bi, In, Ti, Pb, etc., were grown by oscillatory Bridgman technique, high-pressure, modified and vertical Bridgman methods. − It is well-known in the literature that CZT:In is a key artistic material for nuclear radiation detection at RT.…”