GROWTH OF BENZIL CRYSTALS BY VERTICAL DYNAMIC GRADIENT FREEZE TECHNIQUE IN A TRANSPARENT FURNACE

The vertical dynamic gradient freeze technique using a transparent fur nace was applied to the growth of benzil single crystals. A flat-botto m ampoule with a [0001] seed was used for growth. During crystal growt h, dynamic heating profiles were controlled through a computer, and th e growth interface was recorded by a CCD camera. Computer simulation w as also conducted, and the calculated convex interface and dynamic gro wth rate were consistent with the observed ones for various growth con ditions. Conditions for growing single crystals were also determined, and they were mainly limited by constitutional supercooling. As the gr own crystals were clear in appearance, their optical absorption spectr a were insensitive to growth conditions and post-annealing.