Growth optimization and characterization of lattice-matched Al _0.82In _0.18N optical confinement layer for edge emitting nitride laser diodes

We present the growth optimization and the doping by the metal organic chemical vapor deposition of lattice-matched Al _0.82In _0.18N bottom optical confinement layers for edge emitting laser diodes. Due to the increasing size and density of V-shaped defects in Al _1-xIn _xN with increasing thickness, we have designed an Al _1-xIn _xN/GaN multilayer structure by optimizing the growth and thickness of the GaN interlayer. The Al _1-xIn _xN and GaN interlayers in the multilayer structure were both doped using the same SiH ₄ flow, while the Si levels in both layers were found to be significantly different by SIMS. The optimized 8×(Al _0.82In _0.18N/GaN=54/6 nm) multilayer structures grown on free-standing GaN substrates were characterized by high resolution X-ray diffraction, atomic force microscopy and transmission electron microscopy, along with the in-situ measurements of stress evolution during growth. Finally, lasing was obtained from the UV (394 nm) to blue (436 nm) wavelengths, in electrically injected, edge-emitting, cleaved-facet laser diodes with 480 nm thick Si-doped Al _1-xIn _xN/GaN multilayers as bottom waveguide claddings.