Substrate Misorientation, Multi‐Quantum‐Barrier, and Thermal Annealing Effects in MgZnSSe and ZnCdSe Compounds and Blue‐Green II‐VI Light Emitting Devices

Abstract

AbstractMulti‐quantum‐barrier (MQB), substrate misorientation, and thermal annealing effects are investigated in MgZnSSe and ZnCdSe compounds and blue‐green II‐VI light emitting devices. The heterobarrier enhancement of MgZnSSe/ZnSe MQBs is analyzed to be 100 meV, using the experimental band offset of ΔEc ≈ 0.65ΔEg. By use of MQB effect, low threshold current density operation below 1 kA/cm2 can be expected in 480 nm blue emission ZnCdSe/MgZnSSe lasers. For N‐doped MgZnSSe grown on intentionally misoriented GaAs substrates, the decreased net acceptor concentration with misorientation angle is discussed, concluding that the enhanced sulfur incorporation by substrate misorientation plays some role in degradation. It is clarified that ZnSe and ZnSSe are not degraded up to 400°C annealing, while MgZnSSe is even at 350 to 400°C annealing. The light output of ZnCdSe/ZnSe MQW LEDs is enhanced by thermal annealing (325°C, 7 min), by a factor of three.