Interfacial characteristics of Ga0.51In0.49P/GaAs heterostructures grown by metal-organic vapor-phase epitaxy in the temperature range from 600 °C to 730 °C were studied. Photoluminescence (PL) measurements have been used for this purpose. A PL peak with an energy of about 1.425 eV (870 nm) was continuously observed in samples containing the GaInP-to-GaAs interface. Excitation power dependent PL measurements show that this peak belongs to an excitonic recombination. Furthermore, a strong blue-shift of this PL-peak energy was observed as the excitation power increased. We attribute the 870 nm peak to the radiative recombination of spatially separated electron-hole pairs and suggest the type-II band alignment at the ordered GaInP to GaAs heterointerface under growth conditions reported here. Further investigations using x-ray diffraction measurements and simulations with dynamical theory show that the lower and upper interfaces are not equivalent. This explains the absence of type-II transition in most GaAs-to-GaInP lower interfaces.

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Ga0.51In0.49P layers grown by metal-organic vapor-phase epitaxy in the temperature range from 600 to 730 °C and with various Si-doping concentrations were studied. X-ray diffraction was used to observe the ordering in Ga0.51In0.49P layers. The rocking curves of {115} reflection have shown the existence of ordering in Ga0.51In0.49P even in Si-doped samples with an electron concentration up to 1×1019 cm−3. The samples with ordered structure exhibit an additional {1/2, 1/2, 5/2} reflection. However, no such reflection, which is related to group-III sublattice ordering, was observed in GaAs, AlGaAs, and GaInP layers grown at 730 °C. Photoluminescence (PL) and transmission electron diffraction (TED) results confirm these observations. TED patterns and especially the intensity of the additional ordering spots of Ga0.51In0.49P samples are almost unchanged in the studied doping range up to 1.7×1018 cm−3. An increase of PL peak energy attributed to the ordered structure randomization was not observed. The PL peak shift for highly doped Ga0.51In0.49P was found to be only due to the Burstein–Moss effect.

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