Temperature-dependent radiative decay of localized excitons in a type-II GaAs/AlAs superlattice

Journal Article · Sun Aug 15 04:00:00 EDT 1993 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.48.4650· OSTI ID:6261190

Angell, J F; Sturge, M D ^[1]

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1. Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755-3528 (United States)

The low-temperature luminescence intensity decay following pulse excitation of localized excitons in a type-II GaAs/AlAs superlattice is nonexponential. The decay obeys a previously derived theory in which excitons experience a distribution of decay rates corresponding to a Gaussian distribution of [ital X] to [Gamma] scattering matrix elements. At high temperature the decay is exponential with a rate equal to the mean of the distribution. The transition is attributed to excitons motionally averaging the distribution as temperature is increased and thermal delocalization occurs. This paper develops a theory of radiative decay which takes into account motional averaging and is valid at all temperatures. The theory has one fitting parameter [gamma] which is the ratio of exciton lifetime to jump time and determines the extent of averaging performed. Good agreement is found between the theory and experimental data; however, at high excitation intensity and low exciton energy the theory must be modified to take saturation of localized states into account. The temperature dependence of the fitting parameter [gamma] reveals two delocalization processes, the activation energies of which are interpreted as the localization energy and the exciton binding energy.

• DOE Contract Number: FG02-87ER45330
• OSTI ID: 6261190
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 48:7; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360606* -- Other Materials-- Physical Properties-- (1992-)
ALUMINIUM ARSENIDES
ALUMINIUM COMPOUNDS
ARSENIC COMPOUNDS
ARSENIDES
DECAY
EXCITONS
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
LUMINESCENCE
PARTICLE DECAY
PNICTIDES
QUASI PARTICLES
RADIATIVE DECAY
SUPERLATTICES
TEMPERATURE DEPENDENCE