InGaN/GaN Tunnel Junctions For Hole Injection in GaN Light Emitting   Diodes
  InGaN/GaN tunnel junction contacts were grown on top of an InGaN/GaN blue (450 nm) light emitting diode wafer using plasma assisted molecular beam epitaxy. The tunnel junction contacts enable low spreading resistance n-GaN top contact layer thereby requiring less top metal contact coverage on the surface. A voltage drop of 5.3 V at 100 mA, forward resistance of 2 x 10-2 ohm cm2 and a higher light output power are measured in tunnel junction LED. A low resistance of 5 x 10-4 ohm cm2 was measured in a MBE grown tunnel junction on GaN PN junction device, indicating that the tunnel junction LED device resistance is limited by the regrowth interface and not by the intrinsic tunneling resistance. 
Sriram Krishnamoorthy, Fatih Akyol, and Siddharth Rajan
cond-mat.mtrl-sci