Microscopic mechanisms governing exciton-decay kinetics in type-II GaAs/AlAs superlattices
- Department of Physics, Emory University, Atlanta, Georgia 30322 (United States)
- Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)
- Microelectronics Research Center and Department of Physics, Iowa State University, Ames, Iowa 50011 (United States)
We have measured the time- and space-resolved evolution of type-II excitons in GaAs/AlAs superlattices with various AlAs layer thicknesses, at temperatures ranging from 1.8 to 30 K. Our photoluminescence (PL) time decay and transport results demonstrate that the exciton-decay kinetics at low temperatures are entirely determined by intrinsic radiative recombination, whereas at higher temperatures, the PL time decays are dominated by nonradiative defect trapping processes. We show that these nonradiative decays do not occur within the layers but are instead localized at the heterointerfaces. The measured lifetimes at 30 K are consistent with our model calculations based on this interpretation. Furthermore, the superlattice and interface-disorder-induced {Gamma}-{ital X} mixing potentials are determined from our low-temperature exciton lifetimes to be 1.3 and 0.2 meV, respectively.
- Research Organization:
- Sandia National Laboratories (SNL), Albuquerque, NM, and Livermore, CA (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 76473
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 52, Issue 4; Other Information: PBD: 15 Jul 1995
- Country of Publication:
- United States
- Language:
- English
Similar Records
Mechanism of the effect of the electric field of a surface acoustic wave on the low-temperature photoluminescence kinetics in type-II GaAs/AlAs superlattices
Localization of excitons in an indirect gap GaAs/AlAs superlattice