THM growth and homogeneity of 4 inch diameter CdTe single crystals

Abstract

  Recently, the quantitative productivity and qualitative uniformity are becoming important key issues for CdTe and CdZnTe (CZT) detectors in the medical and industrial imaging applications. CdTe is one of excellent materials for room-temperature nuclear radiation detectors with high detection efficiency and good energy resolution, because of its high average atomic number, high resistivity and good charge transport properties. To meet those demands on the room-temperature radiation detectors, we have been carrying out the intensive development and improvement of the Traveling Heater Method (THM), which has been known to grow uniform CdTe and CZT single crystals. We can currently grow high quality Cl doped CdTe single crystals with 75 mm in diameter and 200 mm in length for the mass production, and provide many kinds of nuclear radiation detectors. In this work, we report the THM growth technology of the newly developed 100 mm diameter CdTe single crystal and its characteristics such as the behavior of Te inclusions, resistivity distribution, charge transport properties and the radiation detector performance.