High‐Brightness Blue‐Green Light‐Emitting Diodes on ZnSe Substrates

High‐brightness blue and green light‐emitting diodes (LEDs) are produced based on homoepitaxial films grown by molecular beam epitaxy (MBE) on high quality ZnSe substrates. The substrates are grown by the Eagle‐Picher, seeded physical vapor transport (SPVT TM ) technique. The substrates are twin‐free and contain no low‐angle grain boundaries. Double‐crystal X‐ray diffraction rocking curve studies yield a FWHM 〈400〉 = 11″ to 16″, indicating a crystal quality comparable to that of GaAs substrates. The blue LEDs produce 327 μW (10 mA, 3.2 V), with the light output sharply peaked at 489 nm, and exhibit an external quantum efficiency of 1.3%. The green LEDs produce 1.3 mW (10 mA, 3.2 V) peaked at 512 nm, corresponding to an external quantum efficiency of 5.3%.