Gas source molecular beam epitaxy growth of GaAs/InGaP superlattice as optical confinement layers in 0.98 μm InGaAs/InGaP strained quantum well lasers

GaAs/InGaP superlattices (SLs) grown by gas-source molecular beam epitaxy (GS-MBE) were studied with respect to interface roughness and optical quality. Atomically flat interfaces were obtained at a growth temperature of 460°C by an optimum gas change sequence in which the exposure time of the group-V prior to the growth resumption was as short as 3 s. A GaAs/InGaP SL was introduced into an optical confinement layer (OCL) of a 0.98 μm InGaAs/InGaP strained quantum well laser. Decrease of the threshold current and increase of the slope efficiency were confirmed, which may be due to modifying the equivalent refractive index profile owing to the GaAs/InGaP SL-OCLs. Moreover, the characteristic temperature T₀ at around room temperature (RT) was increased to 300 K.