Short period strained Si/Ge superlattices were grown by mixed source MBE (molecular beam epitaxy) for photoluminescence spectroscopy measurement. We studied the temperature dependence of the photoluminescence spectra. We also studied the effect of RTA (rapid thermal annealing) and deuterium-passivation on the luminescence spectra. In an 8 × 2 Si/Ge superlattice with 60 periods, we observed a strong peak at energy 0.84 eV and a weaker peak at 0.78 eV. We attribute those two peaks to the transition of the exciton localized in the superlattice (the no-phonon peak) and its transverse optical (TO) phonon replica. Those two peaks persisted to a temperature above 140 K, while in samples grown by conventional solid source MBE, the luminescence peaks disappear around 50 K . This is because of the better optical quality of the samples grown by gas source molecular beam epitaxy (GSMBE).
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