High In-content InP-substrate based GaInAsN and GaInAsN QW diode lasers emitting in the 2.2 to 2.3 μm wavelength range

We report on the growth and characterization of high In-content quaternary Ga_1-xIn_xAs_1-yN_y (0.78 < x < 1,y < 0.02), grown by plasma assisted molecular beam epitaxy on InP-substrates. First, the incorporation of nitrogen in high In-content GaInAsN was analyzed by Raman spectroscopy, revealing that already a small amount of Ga in the GaInAsN alloy (x>0.92) leads to an almost complete change from pure In-N bonding to nitrogen atoms bonded to at least on Ga-neighbor. Next, strained Ga_0.22In_0.78As_0.99N_0.01/Al_0.48In_0.$ d5₂As QWs were optimized for long-wavelength emission. In this way room-temperature photoluminescence could be achieved at a wavelength of 2.3 μm for 11 nm wide QWs. Finally, Ga_0.22In_0.78As_0.99N_0.01 QW-diode lasers were realized, employing lattice matched Al_0.15Ga_0.32In_0.53As as the material for the barriers as well as for the separate confinement layers. InP was used for the cladding layers. Ridge waveguide lasers were fabricated without any post-growth thermal annealing. These devices showed pulsed lasing up to a heat sink temperature of 190 K, for which lasing was at 2.23 μm. Higher operating temperatures as well as cw-operation were inhibited by the high threshold current density of almost 2 kA/cm² at 190 K, but room-temperature electroluminescence could be observed at wavelengths up to 2.4 μm. As annealing studies on GaInAsN QW-test structures indicate, post-growth annealing of the laser material will lead to a significant improvement in laser performance.