II-VI SEMICONDUCTOR BLUE-GREEN LASER DEVICE CHARACTERISTICS

Threshold current densities and lasing wavelengths of both ZnSSe/ZnSe/ZnCdSe and ZnMgSSe/ZnSSe/ZnCdSe lasers under short-pulse (100 ns) operation have been measured as a function of temperature. In the second structure, improved electrical confinement and a lower defect density leads to a better T-0 and a higher maximum lasing temperature. In these lasers a room-temperature pulsed threshold current density of 400 A/cm(2) has been obtained. Using ZnSe/ZnTe graded electrical contacts, a laser operating voltage of 6.5 V has been realized. Thermal resistances have been measured in ZnMgSSe/ZnSSe/ZnCdSe lasers. A Value of 31 K/W has been obtained in a 20 mu m stripe laser of 600 mu m length, mounted substrate-up. Both substrate-up and substrate-down mounted lasers meet the thermal continuous-wave lasing condition at room temperature. The relationship between stacking fault density and laser performance has been measured. Defect densities higher than 10(7) cm(-2) significantly increase the lasing threshold. Characteristics of narrow-stripe gain-guided lasers have been measured. Clear changes are seen between short-pulse (100 ns) and longer pulse (800 ns) operation. A simple model that represents thermal index-guiding is used to explain the behavior. The antiguiding parameter is found to be about -1.1.