Photoluminescence and photoreflectance studies in Si/β-/Si(001) double heterostructure

Photoluminescence (PL) and photoreflectance (PR) properties were investigated in Si/β-/Si(001) double heterostructure (DH) samples. The as-grown sample did not show clear PL, but the annealed one showed the PL. In PR spectra, the direct transition energies (Eg) were observed at 0.910–0.935 eV in the samples. The Eg shifted to lower photon energy with the increase of annealing temperature, which indicates a modification of the band structure. These results revealed that the PL was related to the transition at the indirect band gap. The effect of thermal annealing on the PL was discussed.