Single crystal growth of lead-tin telluride
Single crystal growth of lead-tin telluride by the recrystallization method is described. An operating point on the temperature-composition (T-X) diagram is chosen to provide a minute fraction of liquid phase. The solid is equilibrated with the melt which serves as a vehicle for diffusion and crystal growth by recrystallization. The small surface of contact with the container and the relatively low growth temperature compared with melt techniques, minimizes the problem of leaching and facilitates extraction of crystal product.The method has proven especially suitable for the growth of large monocyrstals of centimeter dimensions and control of the lead-tin ratio. Electron microprobe analysis indicates that a sizable volume fraction of the final crystal product has excellent homogeneity with respect to the lead-tin ratio. Although the as-grown bismuth-doped crystals have carrier concentrations on the order of 1019 cm−3, the carrier concentration can be reduced to the low 1017 cm−3 range, with the hole mobility up to 3.5 × 104 cm2 V−1 sec−1 at 77 K, by isothermally annealing the crystals for 120 hours. A high degree of lattice perfection is revealed through surface etch and electron microprobe channeling patterns (CoatesKikuchi patterns).