Optimized interfacial management for InGaAs/GaAsP strain-compensated superlattice structure

In this paper, the interfacial management for InGaAs/GaAsP strain-compensated superlattice (SL) structures with thin wells and barriers and a large number of hetero-interfaces has been investigated. By means of X-ray diffraction (XRD) measurement and high-accuracy in-situ curvature measurement, we found that the hetero-interfaces with substantial lattice mismatch tend to generate interfacial defects, which can be mitigated by the insertion of ultrathin GaAs interlayers. However, an inadequate gas-switching sequence induces unintended atomic content near the hetero-interfaces and in the GaAs insertion layers, which influences the average strain of the structure. It was found effective to extend the stabilization time for the arsenic and phosphorus mixture before GaAsP barrier growth to 3s and to insert an 1s hydrogen purge after InGaAs well growth. Static photoluminescence (PL) and time-resolved photoluminescence (TRPL) results were also used to evaluate the crystal quality of grown structures.