Controlling Te inclusion during direct mixed solution growth of large size CdZnTe crystal

CdZnTe (CZT) is proved to be a perfect material during the fabrication of detectors for X-ray and Gamma ray. However, Te inclusion is one of the main defects in CZT crystal which influences the electrical and spectroscopic properties of the detectors. This paper presents optimization of hot zone design and operating conditions by direct mixed solution growth (DMSG) method in order to reduce the formation of Te inclusion. The growth temperature is 890°C and the growth rate is 5mm/day. With the temperature gradient increased from 20K/cm to 40K/cm, the number of Te inclusion is reduced sharply while the size of Te inclusion is still large. When accelerated crucible rotation technique (ACRT) is introduced, the size of Te inclusion is reduced significantly. Large-size Te inclusion almost disappears under IR imaging. The density of Te inclusion which is larger than 1×10⁴cm³. The resistivity of the as grown crystal is higher than 10¹⁰Ωxcm. At last, the influence of ACRT sequences on Te formation is discussed.