Abstract
The effect of magnetic field on the excitonic photoluminescence line shape has been studied in a high-quality single GaAs-As quantum well grown by the molecular-beam-epitaxy technique. An increase of magnetic field from 0 to 6 T has been found to result in (1) a decrease in the Lorentzian contribution to the line shape from (0 T)=0.504±0.01 meV to (6 T)=0.336±0.01 meV due to the formation of a quasi-zero-dimensional density of states. This leads, in turn, to an increase in the exciton dephasing time due to the inhibition of the carrier relaxation, and (2) an increase in the Gaussian contribution from σ(0 T)=0.24 meV to σ(6 T)=0.39 meV, attributed to the shrinking of the exciton wave function in real space; the last effect causing the exciton to become more responsive to the statistical potential fluctuations at the quantum-well interfaces.
- Received 21 July 1994
DOI:https://doi.org/10.1103/PhysRevB.51.4278
©1995 American Physical Society