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Article Dans Une Revue European Physical Journal: Applied Physics Année : 2007

Contribution of long lived metastable states to the PL of InP dots in indirect band-gap barrier layers

Résumé

We report continuous wave and time resolved photoluminescence studies of self-assembled InP quantum dots grown by metalorganic chemical vapor deposition. The quantum dots are embedded into indirect band-gap In0.5Al0.5P layers or In0.5Al0.3Ga0.2P layers with a conduction band line-up close to the direct-to-indirect crossover. As revealed by photoluminescence spectra, efficient interdiffusion of species from the barrier layers produces (Al,In)P or (Al,Ga,In)P-dots. This interdiffusion creates potential barriers that are repulsive for electrons of X valleys around the QDs. Both samples show a fast exponential decay component with a time constant between 0.5 and 0.7 ns. In addition, the sample with indirect band gap matrix shows a slow non-exponential time-decay, which is still visible after more than 100 µs. The fast component is attributed to direct recombination of electron-hole pairs in the dots whilst the slow component, which follows a power law t^-0.75 results from recombination of holes in the dots and electrons in metastable states around the dots.

Dates et versions

hal-00389970 , version 1 (30-05-2009)

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Citer

Robert Seguin, Thierry Guillet, T. Taliercio, P. Lefebvre, T. Bretagnon, et al.. Contribution of long lived metastable states to the PL of InP dots in indirect band-gap barrier layers. European Physical Journal: Applied Physics, 2007, 37, pp.15. ⟨10.1051/epjap:2007006⟩. ⟨hal-00389970⟩
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