Microstructures on {111} faces of stannic iodide single crystals

Abstract

Single crystals of stannic iodide (SnI,) havebeen grown using the controlled reaction between SnC1, and K I by diffusion process in silica gel medium. Orange to reddish octahedral stannic iodidc crystals up t o 3 -4 mm in size have been grown a t room temperature.Optical studies have been made on the various surface structures of { 11 1 ] faces of the asgrown crystals. On octahedral faces of these crystals, triangular-shaped hillocks with growth layers in the <IlO) directions have been observed. Occasionally, growth spirals on octahedral faces have also been reported. Close loops of growth fronts havebeen investigated and have been interpreted. It has been suggested that two-diemensiona.1 nucleation, spreading and pilling up of triangular growth layers is mainly responsible for the growth and occasionally the growth is due to screw dislocations. The implications are discussed.