Strain-balanced InGaAs/AlInAs/InP quantum cascade laser grown on GaAs by MOVPE

A systematic study was performed to elucidate the properties of strained-layer InGaAs/AlInAs superlattices (SL) on metamorphic buffer layers grown by MOVPE on GaAs substrates. Differences observed in surface morphology indicate relatively tight control over the SL average net-strain is required for the growth of micron-thick SL structures, as needed for quantum cascade laser (QCL) active regions. Using such conditions, 5.7 & mu;m-emitting, strain-balanced InP-based QCLs grown on (001) GaAs were demonstrated with comparable device performance to their counterparts grown on native InP substrate. 3 mm-long and 25 & mu;m-wide uncoated-facets devices, grown on GaAs and having epi-side lateral contacts, provide peak-pulsed output powers of 2.65 W per facet at room temperature. The corresponding threshold-current density and maximum wall-plug efficiency is 1.61 kA/cm2 and 6.0% respectively. HR-XRD measurements of the strain-balanced QCL grown on GaAs show broadened satellite peaks which are well aligned with the peaks from their counterparts grown on InP.