Evidence of type-II band alignment at the ordered GaInP to GaAs heterointerface

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.