Arrigo Addamiano

Some Properties of Zinc Sulfide Crystals Grown from the Melt

Hexagonal zinc sulfide crystals were obtained by controlled cooling of melted zinc sulfide. Both pure and activated zinc sulfide powders were used. The density of pure melt grown crystals was found to be higher than that of natural zinc blende crystals or crystals grown by evaporation. The stability of the pure hexagonal crystals towards transformation to the cubic zinc‐blende structure in the interval of temperature 700–1150°C was investigated. A full conversion to the cubic phase was never observed. The experimental evidence indicates the transition point to be above 1150°C.

Silicon Carbide Light‐Emitting Diodes

Electroluminescent diodes were prepared by the simultaneous diffusion of boron and aluminum at 2150° to 2250°C into nitrogen‐doped, n‐type 6H SiC crystals. These diodes exhibit a typical brightness of 50 ft·L (170 nit) at a current density of 5 A/cm2 for temperatures of 25° to above 200°C. The results of various measurements on these diodes are presented and the anomalous nature of the diffusion is discussed.