Growth optimization and characterization of lattice-matched Al0.82In0.18N 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 Al0.82In0.18N bottom optical confinement layers for edge emitting laser diodes. Due to the increasing size and density of V-shaped defects in Al1−xInxN with increasing thickness, we have designed an Al1−xInxN/GaN multilayer structure by optimizing the growth and thickness of the GaN interlayer. The Al1−xInxN and GaN interlayers in the multilayer structure were both doped using the same SiH4 flow, while the Si levels in both layers were found to be significantly different by SIMS. The optimized 8×(Al0.82In0.18N/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 Al1−xInxN/GaN multilayers as bottom waveguide claddings.

► Al1−xInxN/GaN multilayer was optimized as an optical confinement layer.
► Si incorporation in the Al1−xInxN and GaN is found significantly different.
► Lasing was obtained for the UV (394 nm) to blue (436 nm) wavelengths.
► Evolution of stress was in-situ analyzed by measuring the curvature.