Abstract
According to the degree of superheating the "structure" of associated semiconductor melts with covalent-ionic bondings (AII-BM, AIV-BM) may affct the growth stability and crystal quality very sensitively. The supercooling-superheating function of CdTe (PbTe) shows a step-like increase in the degree of supercooling for melts superheated by more than about 10℃. This behavior differs from semiconductor and semimetal melts with covalent-metallic character (Ge, Bi) because of the destruction of high ordered structural complexes existing up to a critical temperature above the melting point. Any reorganization of such structural elements will not occur during reduction of higher superheating. With increasing deviation from stoichiometry the supercooling increases due to the dissolution of the associates by excess solvent. A correlation between the superheating of the melt and the structure of the nucleation region and density of large angle grain boundaries in CdTe and ZnSe Bridgman crystals has been observed.
