Excess carrier lifetime and ambipolar diffusion anisotropy in a nipi-doped In0.2Ga0.8As/GaAs multiple-quantum-well structure

H. T. Lin, D. H. Rich, A. Larsson

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

The effects of strain-induced structural defects in a nipi-doped In0.2Ga0.8As/GaAs multiple-quantum well sample were studied with time-resolved electron-beam-induced absorption modulation, in which carrier recombination lifetimes and ambipolar diffusion constants are measured with high spatial, spectral, and temporal resolution. Based on a phenomenological model, carrier lifetimes in the limit of weak excitation at room temperature were determined. The lifetime is found to be reduced by a factor of ∼1013 compared to a theoretically calculated value, owing to the presence of strain-induced defects and alternate recombination channels. By using a two-dimensional diffusion model, the ambipolar diffusion coefficients Da along high-symmetry [110], [110], and [100] directions were determined and resulted in an anisotropic behavior such that D[110]a>D[110]a >D[100]a. The anisotropy in diffusion is attributed to corresponding asymmetries in the misfit dislocation density.

Original languageEnglish
Pages (from-to)7014-7020
Number of pages7
JournalJournal of Applied Physics
Volume79
Issue number9
DOIs
StatePublished - 1 May 1996
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy (all)

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