A Method of Growing Single Crystals of Lead Telluride and Lead Selenide

Single crystals of lead telluride measuring up to 1¼-cm diameter and 6 cm long have been grown in sealed silica crucibles by the Bridgman-Stockbarger method of lowering a melt slowly through a freezing level. The crystals have been grown for the purpose of testing the semiconducting and allied properties of lead telluride in that form. Extreme purity of the materials and cleanliness of the crucible have been found essential for successful growth. X-ray tests have shown that the specimens are single crystals. The purest crystal grown so far had a conductivity corresponding to an electron concentration of 5×1014 per cc. Attempts to introduce excess of one of the constituents—lead or tellurium into the crystal lattice during growth have not so far been successful.