Materials Chemistry and Physics, 1 7 (1987) 311-316 SHORT COMMUNICATION 31l GROWTH OF Sb.2S3 SINGLE CRYSTALS BY CHEMICAL VAPOUR TRANSPORT B. VENGATESAN, N. KANNIAH and P. RAMASAMY Crystal Growth Centre, Anna University, Madras - 600 025 (India) Received September 29, 1986; accepted October 31, 1986 ABSTRACT Single crystals of antimony trisulfide have been grown by a chemical vapour transport technique using iodine as the transporting agent. Single crystals were obtained at a much lower temperature when antimony and sulfur in the stoichiometric ratio were taken as the source along with iodine. However when polycrystalline antimony trisulfide was taken as the source with iodine, single crystals were not obtained even at the melting point of Sb2S 3. This observation has been explained on the basis of bond energy values. INTRODUCTION The ferroelectric semiconductor Sb2S 3 has interesting properties such as photoconductivity, with electroop~cal and ~ectromechanical properties. Sb2s 3 has become increasingly important in recent years on account of its photo- electric properties. Its larger photoconductivity in the visible region makes Sb2s 3 attractive for applications as a target material in TV pick-up tubes of the vidicon type and its sensitivity to X-rays is useful in X-ray detection. Zig-zag Sb - S - Sb chains are bound into ribbons along the a - c plane, which ensure a perfect cleavage perpendicular to the b - axis. A quite extraordinary environment exists for one half of the antimony atoms, which are surrounded with five sulfur atoms, each of which in turn is linked to three Sb atoms. The other half of the Sb atoms and the remaining sulfur atoms exhibit the usual trivalency and bivalency respectively [1,2]. ~he compound is prevalently covalent, although an appreciable ionic nature exists in the Sb - S bonds [2]. There has also been evidence of some resonance-covalent bonding [3]. Sb2S 3 belongs to an 0254-0584/87/$3.50 © Elsevier Sequoia/Printed in The Netherlands