Buried Tunnel Contact Junctions in GaN-Based Light-Emitting Diodes

InGaN/GaN multiple-quantum-well light-emitting diode structures utilizing tunnel contact junctions have been demonstrated. The heavily doped p⁺/n⁺ GaN tunnel junctions are located in the upper cladding layers of conventional devices allowing n-type GaN instead of p-type GaN as a top contact layer. Accordingly, metal Ohmic contacts are performed at the same time on the upper and the lower contact layers. The reverse-biased thin tunnel contact junction provides lateral electron current spreading along the n⁺ layer without the use of a semi-transparent electrode and spatially uniform luminescence exhibiting an improved radiative efficiency.