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

Improving the structural, optical, and electronic properties of bulk CZT remains a topic of great interest for producing high quality nuclear imaging material. The work presented here is the result of several experiments whose geometries and materials have been chosen due to their thermal properties. Results are presented for 50 mm CZT ingots grown using furnace elements which have been shown to be conducive to a convex solid–liquid interface shape. A novel crystal growth pedestal was used in this work for in-situ measurements of temperature gradients. The electrical and optical properties of the as grown material are presented. As a result, large crystal grains and volumes have been obtained for 50 mm ingots. The benefit of using this geometry has been demonstrated by comparing CZT ingots grown with and without the SiC pedestal. Gamma spectra are presented for planar devices which have been harvested from the First to Freeze regions which are most influenced by the effects of the SiC pedestal.

► Crystal growth of 50 mm diameter CZT. ► Comparison of experimental results with numerical simulations. ► SiC pedestal used for increasing axial heat flux and reducing super-cooling. ► Effect of SiC pedestal on first to freeze tip studied. ► Effect of cylindrical–conical transition of pBN geometry on grain structure presented.