Low Threshold Current Density In Gainn-Based Laser Diodes With Gan Tunnel Junctions

We demonstrated room-temperature pulsed-operations of GaN-based blue edge-emitting laser diodes (LDs) with both the top and bottom AlInN cladding layers by using GaN tunnel junctions (TJs) grown by metalorganic vapor phase epitaxy. The LDs with a 1.2 mm cavity length and a 15 mu m ridge width were fabricated. We obtained a low threshold current density of 0.9 kA cm(-2) with facet coating. We found that while an optical absorption loss in the waveguiding layer was reduced with a low Mg concentration (3 x 10(18) cm(-3)), that in a highly doped TJ could be an obstacle to obtain further improvements of the laser characteristics.