Role of arsenic clusters in carrier recombination in low-temperature grown AlGaAs/GaAs multiple quantum wells

The low-temperature grown AlGaAs/GaAs multiple quantum well structures were characterized by photoluminescence (PL) spectroscopy. The samples were grown at 270-400 degrees C and annealed at 500-900 degrees C. After anneal, photoluminescence quenching was observed for the samples grown at temperatures below 350 degrees C, and found to show a strong dependence on the growth and anneal temperatures. The luminescence intensity for the PL-quenched sample exhibits a power law dependence on the excitation level with an exponent close to 2, indicating a bimolecular recombination process in parallel with strong nonradiative recombination. The photoluminescence quenching upon anneal is attributed to the formation of arsenic clusters that serve as new nonradiative recombination channels. (C) 1998 American Institute of Physics