Studies of photoreflectance spectra in Cd(x)Mn(1-x)Te/CdTe superlattices with high compositions

Cd(1–x)Mn(x)Te/CdTe superlattices were grown by molecular beam epitaxy with a CdTe buffer layer on GaAs(001) substrate. Photoreflectance spectra were performed on Cd1–xMnxTe/CdTe superlattices with high compositions of x = 0.4, 0.8 at room temperature and liquid nitrogen temperature. The exciton transitions related to the heavy (H) and light (L) holes of 11H, 11L, 22H, and 33H are observed. After taking into account the strain-induced and quantum confinement effects, the theoretical calculations are in good agreement with the photoreflectance measurement results except x = 0.8 of 33H. Photoluminescence measurements were also performed at room temperature and low temperature in order to compare with our photoreflectance results. Our results show that the photoreflectance spectroscopy technique is a powerful probe for the study of quantized state structures in superlattices systems.