Abstract

Large single crystals of Zn_1-xCd_xS (x0.07) weighing up to 5 g were grown by iodine transport in closed ampoules in the growth temperature range of 700–1150°C. Nucleation control has been achieved in three ways: growth in ampoules of inner diameter 8 mm, by using tapered ampoules, and growth on a seed. The best results were achieved when the iodine content was 1–2.5 mg/cm³ and the ampoules pulled with a rate correlated to the crystal-charge distance and the temperature gradient in crystal zone. Comparison of theoretically predicted growth rates with those experimentally obtained show that crystals of good quality grow in a diffusion-controlled system. The problem of instability effects in the growth process is discussed.