High-brightness II–VI light-emitting diodes grown by molecular-beam epitaxy on ZnSe substrates

High-brightness blue and green light-emitting diodes (LEDs) based on II–VI double heterostructures (DHs) have been successfully grown by molecular-beam epitaxy (MBE) on (100) ZnSe substrates. These LED structures consist of a 500–1000 Å thick active region of undoped blue-emitting Zn0.9Cd0.1Se/ZnSe multiple quantum wells or a green-emitting ZnTe0.1Se0.9 single quantum well sandwiched between a 2–3 μm thick n-type ZnSe:Cl layer and a ∼1 μm thick p-type ZnSe:N layer. Operated at 10 mA (3.0 V), the blue LEDs produce 327 μW of light output sharply peaked at 489 nm, corresponding to an external quantum efficiency of 1.3%. The green LEDs generate 1.3 mW of light peaked at 512 nm with a corresponding external quantum efficiency of 5.3%. In terms of photometric units, the luminous efficiencies for these II–VI blue and green LEDs are 1.7 and 18.0 lm/W, respectively.