Crystal Growth of Lithium Tetraborate (Li2B4O7)

Abstract

A good quality single crystal of Li2B4O7, up to 23 mm in diameter and 80 mm in length, has been successfully grown at a crystal pulling rate of 1 mm/h and the seed rotation rate of 6 r.p.m. by an automatic diameter control (ADC) of the Czochralski method. This crystal was very transparent and colourless, and possessed large regions free of any optical in homogeneity. Macroscopic defects such as cores appeared in some growing crystals have been discussed. Cores generated in growing crystals largely depended on the crystal pulling rate, rapid temperature change during the crystal growth and purity of starting materials.