Bridgman growth of bismuth tellurite crystals

摘要

The photorefractive crystal, Bi_2TeO_5, was grown by the modified Bridgman method for the first time. High purity Bi_2O_3 and TeO_2 were used as starting materials and were mixed thoroughly with molar ratio of Bi_2O_3/TeO_2 = 1:1. Platinum crucible was fabricated with a seed well of 10 mm in diameter and several folds were pressed so that the spontaneous nuclei could be eliminated through competition. The crucible was sealed during the growth so that the evaporation of TeO_2 was controlled effectively. By optimizing growth parameters, transparent and crack-free Bi_2TeO_5 crystal up to 25 mm in diameter and 40 mm in length was grown successfully.