Proceedings Article | 20 April 2017
KEYWORDS: Semiconductor lasers, Current controlled current source, Quantum wells, Gallium arsenide, Annealing, Laser damage threshold, Pulsed laser operation, Waveguide lasers, Luminescence
Ga(AsBi) quantum well (QW) active regions are an alternate to dilute-nitride QWs for achieving lasers in the telecom wavelength regions (λ~1.3-1.55μm) on GaAs substrates. Ludewig et al first reported the successful operation of Ga(AsBi) single quantum well laser in 2013 [1] with low threshold current densities, Jth=1.56kA/cm2 where (AlGa)As was used as a barrier material for low Bi-content QWs to improve the electron confinement in the conduction band and reduce thermally activated carrier leakage from the QW. We implement here the use of tensile-strained Ga(AsP) as a QW barrier material, providing carrier confinement as well as potential for strain-balancing. Laser structures employing a single GaAs0.976Bi0.024 quantum well (SQW) with either GaAs0.8P0.2, Al0.15Ga0.85As, or GaAs barrier materials were grown by MOVPE on a nominally singular (001) GaAs substrate Ridge waveguide lasers, 25μm-wide and 1mm-long ridge, were fabricated and characterized under pulsed current conditions. The threshold current densities for devices are 5.9kA/cm2 and 5.8kA/cm2 for GaAsP barriers and Al0.15Ga0.85As barriers respectively, with a lasing wavelength of 960nm. Devices with GaAs barriers only lased at higher currents for a short wavelength transition ~900nm. While threshold currents are relatively high, no post growth thermal annealing was performed on these laser materials. Thermal annealing studies will be presented indicating significant improvement in QW luminescence and reduction in Jth can be achieved after the post-growth in-situ annealing.
[1] Ludewig, P., Knaub, N., Hossain, N., Reinhard, S., Nattermann, L., Marko, I. P., and Volz, K. 2013. Appl. Phys. Lett., 102(24), 242115.
