AlGaAs/InGaP interfaces in structures prepared by MOVPE

Al0.3Ga0.7As/In1−xGaxP structures were prepared by low-pressure MOVPE. Lattice matched and strained ones with top In1−xGaxP layers as well as reverse ones with top Al0,3Ga0,7As layers were examined. The structures were studied by photoluminescence, X-ray and atomic force microscope (AFM) methods. An additional photoluminescence peak from the Al0.3Ga0.7As/In1−xGaxP interface was observed in our samples and it was attributed to a type-II band offset. A conduction band offset of 0.121 eV was measured in the Al0.3Ga0.7As/In0.485Ga0.515P lattice-matched structure and a linear dependence of the conduction band offset on In1−xGaxP composition, with a zero offset in the Al0.3Ga0.7As/In0.315Ga0.685P structure, was determined. The valence band discontinuity had a nearly constant value of 0.152 eV.