Composition variation of InGaAsP grown on (111)B faceted V-groove InP substrates by gas source molecular beam epitaxy

The authors have grown 40 nm thick InGaAsP layers by gas source molecular beam epitaxy on V-groove etched (100) InP substrates. Transmission electron microscopy (TEM) has been used to examine defect information and layer thickness; energy dispersive X-ray analysis (EDX) has been used to measure the composition variation along the sidewalls and at the bottoms of the V-grooves. Based on the measured spatial distribution of composition, the strain and energy bandgap distributions are calculated. These are compared to low-temperature photoluminescence energy-bandgap measurements.