MOVPE OF IN(GAAS)P/INGAAS MQW STRUCTURES

We report on MOVPE growth of In(GaAs)P/InGaAs multi-quantum-well (MQW) structures. The growth was carried out at a reactor pressure of 20 hPa in an horizontal lamp heated cold wall reactor with rectangular inner liner tube using as group III elements TMIn and TMGa and as group V elements 100% AsH3 and PH3. Wedge transmission electron microscopy (WTEM), photoluminescence (PL) measurements at 2 K and 300 K, and X-ray double crystal diffractometry (DCD) were used for characterization. WTEM technique demonstrates monolayer interfaces and an excellent periodicity of the structures. This is in addition proven by DCD measurements with satellite peaks up to the 8th order. Separate confinement MQW (SCMQW) laser structures with InGaAsP barriers were grown and fabricated to Broad Area (BA) lasers. As a best value we measured threshold current densities of 800 A/cm2. A graded refractive index separate confinement heterostructure (GRINSCH) MQW laser structure with 7 InGaAsP grading layers was also grown and showed very homogeneous laser results with a 20% increased quantum efficiency as compared to SCMQW structures.