Micro-light-emitting diodes with III–nitride tunnel junction contacts grown by metalorganic chemical vapor deposition

Micro-light-emitting diodes (µLEDs) with tunnel junction (TJ) contacts were grown entirely by metalorganic chemical vapor deposition. A LED structure was grown, treated with UV ozone and hydrofluoric acid, and reloaded into the reactor for TJ regrowth. The silicon doping level of the n ++ -GaN TJ was varied to examine its effect on voltage. µLEDs from 2.5 × 10 −5 to 0.01 mm 2 in area were processed, and the voltage penalty of the TJ for the smallest µLED at 20 A/cm 2 was 0.60 V relative to that for a standard LED with indium tin oxide. The peak external quantum efficiency of the TJ LED was 34%.