REMARKABLE IMPROVEMENT IN EMISSION EFFICIENCY OF ZNCDSE ZN(S)SE LEDS BY THERMAL ANNEALING/

Thermal annealing effects on optical and electrical characteristics fo r p-type and n-type II-VI compound layers (ZnSe, ZnSSe, and MgZnSSe) a nd on the emission efficiency of ZnCdSe/Zn(S)Se 6 quantum well (QW) li ght emitting diodes (LEDs) grown by molecular beam epitaxy were invest igated. It was clarified that serious degradation of optical and elect rical characteristics was not observed up to an annealing temperature of 400 degrees C. In the case of p-MgZnSSe, the maximum permitted anne aling temperature was lower than that of Zn(S)Se. The light output of the ZnCdSe/Zn(S)Se multi QW LEDs was enhanced by a factor of three at optimum thermal annealing conditions. The study suggests that this the rmal effect for LEDs was produced by the improved crystal quality of Z nCdSe QWs by thermal annealing.