ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
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], [11¯0], and [100] directions were determined and resulted in an anisotropic behavior such that D[110]a(approximately-greater-than)D[11¯0]a (approximately-greater-than)D[100]a. The anisotropy in diffusion is attributed to corresponding asymmetries in the misfit dislocation density. © 1996 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.361467
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