Photoluminescence spectroscopy and carrier lifetime measurements were used to characterize the optical properties of defects in multiple quantum well structures which had been grown at low temperatures. Two sets of samples were grown at 400C, by means of molecular beam epitaxy, onto nominal (001) and miscut [4º-off (001) towards (111)A] GaAs substrates, respectively. The samples were then subjected to rapid thermal annealing (600 to 800C, 30s). It was found that, after annealing, 2 defect-related photoluminescence features appeared in the samples which had been grown onto nominal (001) substrates, but not in those grown on miscut substrates. The carrier lifetimes were about 31 and 5ps in as-grown samples grown on the nominal and miscut (001) substrates, respectively. The differing photoluminescence spectra and carrier lifetimes were attributed to differing structures of the AsGa-like defects which formed during low-temperature growth.

Influence of (001) Vicinal GaAs Substrates on the Optical Properties of Defects in Low-Temperature Grown GaAs/AlGaAs Multiple Quantum Wells M.H.Zhang, Q.Li, Y.F.Zhang, Q.Huang, J.M.Zhou, Z.Y.Xu: Applied Physics Letters, 1999, 75[4], 504-6