Structural and optical properties of very high quality GaAs/AlGaAs multiple quantum well structures grown on (111)A substrates by MOVPE

We report an investigation of the structural and optical properties of the first high quality GaAs/AlGaAs multi-quantum-well structures grown on (111)A substrates by the metallorganic vapor phase epitaxial process at the relatively low temperature of 600°C. By high-resolution X-ray diffractometry it is shown that the structure analyzed has a good crystal quality and period reproducibility. The structural and optical properties were also investigated by photoluminescence and photoreflectance spectroscopies. A photoluminescence linewidth of 12.3 meV at 11 K indicates that the well length (105 Å) fluctuation over 10 periods is at most ±3 monolayers. A detailed analysis of the photoreflectance spectrum at 11 K permits an excellent identification of all the allowed and also weakly allowed optical transitions expected for this structure, further demonstrating that the heterointerfaces are abrupt and smooth