GaN-based light emitting diodes with tunnel junctions

We have demonstrated hole injection through a tunnel junction embedded in t he GaN-based light emitting diode structure. The tunnel junction consists o f 30 nm GaN:Si++ and 15 nm InGaN:Mg++ grown on a GaN-InGaN quantum well het erostructure. The forward voltage of the light emitting diode, including th e voltage drop across the reverse-biased tunnel junction, is 4.1 V at 50A/c m(2), while that of a standard light emitting diode with a conventional con tact structure is 3.5 V. The light output of the diode with the tunnel junc tion is comparable to that of the standard device. This tunnel junction eli minates the need for a highly resistive p-AlGaN cladding layer in short-wav elength laser diodes and the semi-transparent electrode required for curren t spreading in conventional GaN-based light emitting diodes.