Dislocation etching of tin iodide single crystals

Abstract

Single crystals of tin-iodide (SnT,) have been grown using the controlled reaction between SnCl, and K I by diffusion process in gel medium. As grown (010) surfaces of the crystals have been optically studied. Characteristic etch pits have been observed on them. This suggests that SnI, crystals might go into dissolution in the acid-set gel. By successively etching (010) surfaces in a mixturc of ammonia,, acetic acid, and CdCl, solution, it is established that the pits indicate the site of dislocations in the crystals. This is further confirmed by comparing the etch patterns before and after chemically polishing (010) surfaces. The average dislocation density in the crystals have been evaluated and found to be 3.2 x lo3 a,nd the implications are discussed.