Photoluminescence and electroluminescence from a Si/SiO 2 superlattice have been measured. They show similar characteristics and exhibit an inhomogeneously broadened photoluminescence band peaked at 2.06 eV. The excitation spectrum indicates that excitations occur in the Si layers. The insensitivity of the luminescence spectrum and decay to temperature and excitation wavelength suggests that luminescence originates from transitions between localized defect states. These localized states are most likely defect states residing at the Si/SiO 2 interfaces, because there should be a significant concentration of defects at the interface and SiO 2 due to the large lattice mismatch and the amorphous state. The close proximity of these states offers a more rapid transition path for the excited electrons. An energy band diagram of the superlattice is constructed based on our results.
Scopus Subject Areas
- Physics and Astronomy(all)