Influence of substrate misorientation on the photoluminescence and structural properties of InGaAs/GaAsP multiple quantum wells

InGaAs/GaAsP multiple quantum wells (MQWs) were grown by metal-organic chemical vapor deposition on vicinal GaAs (001) substrates with different miscut angles of 0 degrees, 2 degrees and 15 degrees towards [110]. The crystal structures of InGaAs/GaAsP were characterized by high-resolution X-ray diffraction and Raman spectroscopy. The surface morphologies of InGaAs/GaAsP MQWs were observed by atomic force microscopy. The mechanisms for step flow, step bunching and pyramid growth on 0 degrees, 2 degrees and 15 degrees misoriented substrates were discussed. The results provide a comprehensive phenomenological understanding of the self-ordering mechanism of vicinal GaAs substrates, which could be harnessed for designing the quantum optical properties of low-dimensional systems. From low-temperature photoluminescence, it was observed that the luminescence from the MQWs grown on a vicinal surface exhibits a red-shift with respect to the 0 degrees case. An extra emission was observed from the 2 degrees and 15 degrees off samples, indicating the characteristics of quantum wire and pyramidal self-controlled quantum-dot systems, respectively. Its absence from the PL spectrum on 0 degrees surfaces indicates that indium segregation is modified on the surfaces. The relationship between InGaAs/GaAsP MQWs grown on vicinal substrates and their optical and structural properties was explained, which provides a technological basis for obtaining different self-controlled nanostructures.