Growth of Sillenite-Structure Single Crystals.

The main processes for preparing bulk single crystals and films of photorefractive and piezoelectric Bi12M xO20±δ (M = Group II–VIII elements) sillenite compounds are considered. Experimental data are summarized on the crystal growth of Bi12M xO20±δ from the melt and under hydrothermal conditions, and the key morphological features of sillenites are analyzed. Various types of macroscopic growth defects in sillenite-type crystals are described, and their origin is discussed. The compositions of second-phase inclusions in undoped and doped (Group I–VIII elements) Bi12SiO20, Bi12GeO20, and Bi12TiO20 single crystals are presented, and the main physicochemical properties of various Bi12M xO20±δ crystals are summarized. [ABSTRACT FROM AUTHOR]