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 6.67×104/cm2 to 2.36×103/cm2 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.