Influence of Free-space Volume in Ampoule on Defects of CdZnTe Crystal Grown by Bridgman Method

CdZnTe crystal was grown by Bridgman method. The relationship between the free-space volume in the ampoule and the defects in CZT, such as Te inclusion and Cd vacancy, was studied by IR transmission microscopy and positron annihilation technique (PAT). With the decrease of the free-space volume in the ampoule, the density reduced from 6.67×10/cm to 2.36×10/cm with the reduction of Te inclusions. The average positron lifetime decreased from 325.4 ps to 323.4 ps with the decrease of the free-space volume, indicating a reduction of Cd vacancies. The improvement of IR transmittance and resistivity of CZT further demonstrates that lowing the free-space volume in the ampoule can effectively depress the defects in CZT crystal.