Low threshold current density in GaInN-based laser diodes with GaN tunnel junctions

Abstract 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 μ 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 × 10 18 cm −3 ), that in a highly doped TJ could be an obstacle to obtain further improvements of the laser characteristics.