Impact of p-GaN Thermal Damage and Barrier Composition on Semipolar Green Laser Diodes

Dark triangle defects (DTDs) are common nonradiative defects in semipolar
$(20\bar{2}1)$
oriented green quantum wells (QWs), commonly used in green laser diodes (LDs). We show that DTDs do not appear “as-grown,” and DTD size depends strongly on post-QW-growth annealing time and temperature. Using low temperature p-GaN, we prevent catastrophic QW damage and directly compare LDs with GaN and AlGaN containing barriers. The GaN barrier LD exhibited a lasing wavelength of 511 nm, reduced operating voltage, and the lowest threshold current density, likely due to enhanced optical confinement factor and the elimination of very low growth temperature AlGaN in the active region.